Muhammad bin Ya‘qub Kolaini, by his notes from Muhammad bin Soleiman, quoting his father, Sodair, relates that:
قال: كنت انا و ابو بصير و يحيى البزاز و داود بن كثير فى مجلس ابى عبد الله عليه السّلام اذ خرج علينا و هو مغضب، فلما اخذ مجلسه قال: يا عجبا لاقوام يزعمون انا نعلم الغيب، لا يعلم الغيب الا الله عز و جل، لقد هممت بضرب جاريتى فهربت منى فما علمت فى اى بيوت الدار هى. قال: سدير فلما ان قام من مجلسه و صار فى منزله، دخلت انا و ابو بصير و ميسر و قلنا: جعلنا الله فداك سمعنا و انت تقول كذا و كذا فى امر جاريتك و نحن نعلم انك تعلم علما كثيرا و لا ننسبك الى علم الغيب!؟ قال: فقال: يا سدير اما تقرأ القرآن؟ قلت: بلى. قال: فهل وجدت فيما قرات من كتاب الله عز و جل: قال الذى عنده علم من الكتاب انا آتيك به قبل ان يرتد اليك طرفك؟ قال: قلت: جعلت فداك قد قراته. قال: فهل عرفت الرجل و هل علمت ما كان عنده من علم الكتاب؟ قال: قلت: اخبرنى به. قال: قدر قطرة من ماء البحر الاخضر، فما يكون ذلك من علم الكتاب؟ قال: قلت: جعلت فداك: ما اقل هذا! فقال: يا سدير: ما اكثر هذا ان ينسبه الله عز و جل الى العلم الذى اخبرك به. يا سدير فهل وجدت ما قرات فى كتاب الله عز و جل ايضا: قل كفى بالله شهيدا بينى و بينكم و من عنده علم الكتاب؟ قال: قلت: قراته جعلت: فداك. قال: فمن عنده علم الكتاب كله افهم ام من عنده علم الكتاب بعضه؟ قلت: لا، بل من عنده علم الكتاب كله. قال: فاومى بيده الى صدره و قال: علم الكتاب و الله كله عندنا، علم الكتاب و الله كله عندنا. و روى هذا الحديث ايضا الصفار فى «بصائر الدرجات» بتغيير يسير بزيادة و نقصان. 
[Sodair Seirafi] says: ‘Abu Basir, Yahia Bazzaz, Dawood bin Kathir and I were in the assembly of Abi Abdillah, the Holiness Imam Ja‘far Sādiq, Upon Him be Peace, when suddenly, the Holiness, in anger, entered the assembly-room and after taking his place, he said: ‘It is very strange that some people think that we have the omniscience and have the knowledge of the secrets! No one, except Allah, Glory to Him, is the Omniscience and owns the knowledge of the secrets.
I just wanted to chastise and correct my slave-girl but she ran away and I could not find which room she was hiding!’
Sodair says: When the Holiness stood up and left the assembly for his house, Abu Basir, Moyassar and I followed him and asked: ‘May we be made your sacrifice, today we heard what you said about that slave-girl what she did and how you acted against her, and we are not here to say that you are omniscience and have the knowledge to read the secrets, however, we know that you are full with knowledge.’
The Holiness asked: ‘O Sodair, have you recited the Qur’an?’
I aid: ‘Yes, I have.’
Then, he stated: ‘Have you ever read this verse in the Qur’an:
قال الذى عنده علم من الكتاب انا آتيك به قبل ان يرتد اليك طرفك؟
One, who had the knowledge about the [Divine] Book said to Solomon, ‘I shall bring you the Throne of Belghais in the twinkling of an eye [from the town of Sheba]!’
I said: ‘Yes, I have read it.’
(As the Holiness Solomon has invited Belghais, the queen of the town of Sheba to embrace Islam, so that they not to have the sense of superiorities in front of the Holiness Solomon, they all came to Solomon in the state of surrendering. Then, once while he was sitting in his assembly with the tribe of the jinn, who were dominated by the Holiness, he said: ‘Who is that to bring me the Throne of Belghais, but before their coming to me in surrender?’
قَالَ يَا أَيُّهَا الْمَلأ أَيُّكُمْ يَأْتِينِي بِعَرْشِهَا قَبْلَ أَنْ يَأْتُونِي مُسْلِمِينَ؟
‘… He said, ‘O Councilmen, which of you can bring me her throne before they come to me in surrender?’
قَالَ عِفْريتٌ مِنَ الْجِنِّ أَنَا آتِيكَ بِهِ قَبْلَ أَنْ تَقُومَ مِنْ مَقَامِكَ وَإِنِّي عَلَيْهِ لَقَوِيٌّ أَمِينٌ قَالَ الَّذِي عِنْدَهُ عِلْمٌ مِنَ الْكِتَابِ أَنَا آتِيكَ بِهِ قَبْلَ أَنْ يَرْتَدَّ إِلَيْكَ طَرْفُكَ فَلَمَّا رَآهُ مُسْتَقِرًّا عِنْدَهُ قَالَ هَذَا مِنْ فَضْلِ رَبِّي لِيَبْلُوَنِي ءَأَشْكُرُ أَمْ أَكْفُرُ. 
[Among the councilmen in the assembly,] a devil from the tribe of the jinn said: ‘I have such a power in bringing her Throne, and I lay a wager that before you get to stand on your feet I shall present it in front of you.’
Then, one, who knew the whole knowledge of the Book, (Aasif, bin Barkhia, who was the Successor and the Minister of Solomon), said: ‘But, I shall bring the Throne of Belghais to you in the twinkling of an eye’ – [and he did].
When Solomon saw that the Throne of Belghaise was standing in front his eyes, he said: ‘This is some of my Lord’s bounty, so He may test me [to see] whether I am thankful or thankless [to his endless bounties].’
Then the Holiness asked: ‘Do you know the man who presented the throne in the twinkling of an eye? And do you know how much he knows of the Divine Book?’ I said: Please, you inform me about it. The Holiness stated: ‘He knows as little as a drop out of an ocean of it – yes, Aasif bin Barkhia had that much of knowledge from the Divine Book! I said: May I be made your sacrificed, then, this is very little. It is because the knowledge of the Divine Book is specified to Allah, Glory be to Him, now I am telling you how immense it is! O Sadir have come across this verse in the Book of Allah where He states: “O Messenger, say to the disbeliever of the Quraish that the best and most sufficient witness between you and I is Allah the one who has the whole knowledge of the Boom?”
I said: May I be made your sacrifice, I have recited this verse.
The holiness stated: ‘Now, is one who knows the whole knowledge of the Book wiser or one knows some parts of it?’
I answered: Of course he who has the whole knowledge (which is on a scale of the Pacific Ocean in front of a single drop) is wiser. The Holiness nodded and pointed to his chest with a finger saying: ‘By Allah, the whole knowledge of the Book is here, By Allah, the whole knowledge of the Book is here; and Allah has assigned it for us, the Household.’
And Saffar has related this narrative “Basaeer ad-Darajat” but with little differences in the words and phrases; and Ghandouzi, the Hanafi, has related it in brief. 
And also, Ghandouzi has related Omar bin Ozina who had quoted the Holiness Imam Sādiq, Upon Him be Peace, saying:
قالَ أميرُالمُؤمِنِينَ عليه السّلام: ألا إنَّ العِلمَ الَّذى هَبَطَ بِهِ آدَمُ عليه السّلام مِنَ السَّماءِ إلَى الارضِ وَ جَميعَ مَا فُضِّلَتْ بِهِ النَّبِيُّونَ الى خاتَمِ النَّبِيِّينَ فِى عِتْرَة خَاتَمِ النَّبِيِّينَ صلّى الله عليه و آله و سلّم. 
The Commander of the believers said: ‘O people, be aware that the knowledge which Adam, the father of man, brought down on the earth from the heaven and that included all dignities, perfections and the knowledge of all the messengers – from the beginning to the Last one who had privilege upon the entire human being are all brought together with the Household of the Seal of the Messenger, Bless be to Him and his Descendants,
And with his documents from Walid Samman, Sheikh Tabarsi related in the “IHTIJAJ” that:
قالَ: قالَ لى أبوُ عَبْدِ اللهِ عليه السّلام: مَا يَقُولُ النّاسُ فى اولى العَزْمِ وَ عَنْ صاحِبكُمْ- يَعنى أميرَالمُؤمِنِينَ-؟ قالَ: قُلْتُ: مَا يُقَدِّمُونَ عَلى اولِى العَزْمِ أحَداً. فَقالَ: إنّ اللهَ تَبارَكَ وَ تَعالَى قَالَ عَن مُوسَى: «وَ كَتَبْنَا لَهُ فِى الالْوَاحِ مِن كُلِّ شَىءٍ مَوعِظَة» وَ لَم يَقُلْ كُلَّ شَىءٍ. وَ قَالَ عَن عيسى: «وَ لِيُبَيِّنَ لَكُم بَعْضَ الَّذِى تَخْتَلِفُونَ فِيه» وَ لَمْ يَقُلْ كُلَّ الَّذى تَخْتَلِفُونَ فِيهِ. وَ قَالَ عَنْ صَاحِبِكُمْ يَعنى أميرَالمُؤمِنِينَ عليه السّلام: «قُلْ كَفَى بِاللَهِ شَهِيدًا بَيْنِى وَ بَيْنَكُم وَ مَن عِندَهُ عِلْمُ الْكِتب»، فَقَالَ اللهُ عَزَّ وَ جَلَّ: «وَ لَا رَطْبٍ وَ لَا يَابِسٍ إِلَّا فِى كِتبٍ مُّبِينٍ»، وَ عِلْمُ هَذَا الكِتَابِ عِنْدَهُ. 
[Walid Samman] says: The Holiness Imam Ja‘far Sādiq, Upon Him be Peace, told me: ‘What are people’s opinions about the arch- prophets as well as your Master, the Commander of the believers?’ I said: They consider no one to have priorities upon the arch prophets. The Holiness stated: ‘Allah, Glory be to Him, states concerning Moses: “And We wrote a bit of everything for him on the Tablets for instruction and as an analysis of everything;” but He did not state the whole things. And concerning Jesus He states: “He has come to you from Allah to make clear something that you disagree in;” but He has not stated everything: However, concerning your Master, the Commander of the believers, He says: “[O Messenger,] say: The best witness between you and I is Allah and he who possesses the whole knowledge of the Book.” And moreover, Allah states: “Neither a grain in the darkness of the earth, nor any tender or withered [stalk falls] unless it is in a clear Book;” and Allah has bestowed the knowledge of this Book to the Commander of the believers.’
And Ghandouzi, the Hanafi has related this narrative in brief. 
And Ali bin Ibrahim has related in from Omar bin Ozaina his commentary:
قالَ: قَالَ أبو عَبْدِ اللهِ عليه السّلام: «الَّذِى عِندَهُ عِلْمُ الْكِتبِ» أميرُالمؤمنين عليه السّلام. و سُئِلَ عَنِ الَّذى عِندَهُ عِلْمٌ مِنَ الكِتَابِ اعْلَمُ أمْ مَنِ الَّذى عِندَهُ عِلْمُ الكِتَب. فقالَ: مَا عِلْمُ الَّذى عِنْدَهُ عِلْمُ مِنَ الكِتَبِ إلّا بِقَدَرِ مَا تَأخُذُ البَعُوضَة بِجَناحِها مِن ماء البَحْرِ. قالَ اميرُ المؤمنينَ: ألا إنَّ العِلْمَ الَّذى هَبَطَ بِهِ آدَمُ مِنَ السَّمَاءِ الَى الارضِ وَ جَميعَ مَا فُضِّلَتْ بِهِ النَّبِيُّونَ الَى خَاتَمِ النَّبِيِّين فِى عِتْرَة خَاتَمِ النَّبِيِّين. 
He said: ‘The Holiness Imam Sādiq, Upon Him be Peace, stated: ‘He who owns the knowledge of the Book is the Commander of the believers.’ And when he was asked whether one who had the part of the knowledge of the Book was wiser or one who owned the whole knowledge of it, the Holiness answered: ‘He who has a bit or part of the knowledge of the Book is like a narrow stream taking a wing of a gnat away from the sea.’
In this connection, the Commander of the believers, Upon Him be Peace, has stated: ‘The entire knowledge that Adam brought with him down to the earth from the heavens, and all the dignities and knowledge of the messengers up to the Seal of the prophets are with the Household of the Messenger.’
And Ghandouzi, the Hanafi, has related this narrative in brief.
Anyhow, by these narratives and explanations, it became quite clear that the purpose of the learned on the Book in the foregoing verse is only the Holiness Commander of the believers, Upon Him be Peace, thus, any other probability is wrong and unreliable. Then, why the Commander of the believers, who, from the beginning of the Holiness Messenger’s prophetic mission, was the closest companion of the Generous Messenger all time: at night and during the day, on a journey or at home, in the battle or peaceful state cannot be the sole learned on the Book but that Abdullah bin Salam?!’
Apart from this, Abdullah bin Salam, as it is understood from his life history, had not even paid allegiance for the Imamate of the Commander of the believers; therefore, how does it come that the Messenger of Allah to take him at the level of Allah to witness for his prophetic mission!
In “Rijal”, Barqi has considered him to be of the companions of the Messenger;  and also in “Rijal”, book one,  ibn Dawood has also considered him as the trustee, though in “ Tanghih al-Maghal” he has said: Most of the people whom ibn Dawood has mentioned in the first book again he has brought their names in his second book which is for the weak and ignorance. 
Moreover he says: Abdullah bin Salam is an unknown character to me, that is, I do not believe his narratives. And the three caliphs have considered his men to be of the companions of the Messenger of Allah, and they have said in the beginning he was and a Jew then he chose the Christianity, and after that he united with Bani Qainogha by oath – and was of the off spring of Yusuf bin Ya‘qūb. His name, in the pagan state of the Arabs, was Hasin and when he embraced the Islam, the Messenger of Allah called him Abdullah; and according to the history of Abu Ahmad Askari, he died in the year forty-three of Hijri. Then, he says: His bad condition and untruthfulness can be well understood in the preface of “The Nahj-ul-Balagha” written by ibn Abi-al-Hadid.
Ibn Abi-al-Hadid says: After Othman, when people began swearing allegiance with the Commander of the believers, the Holiness sent for a group to come and pay homage. Some people asked the Holiness: Do you not send after Hisan bin Thabit, Ka‘b bin Malik and Abdullah bin Salam?
The Holiness said:
لَا حَاجَة لَنَا فِيمَنْ لَا حَاجَة لَهُ فِينا...
‘We need not anyone’s help who needs not our help.’ 
And, after relating this narrative of the Commander of the believers by ibn Abi al-Hadid, the most learned Muhammad Taghi Shoshtari says: Tabari and Masoudi have also mentioned this statement of the Holiness about him. 
However, in the Sunnite’s authorities, I did not find his life history in the “Tabaghat” of ibn Sa‘d and the “Mizan al-E‘tedal”, however, ibn Abdur-Birr has mentioned his biography up to where he says: Some of the commentators say, the blissful verse:
وَ شَهِدَ شَاهِدٌ مِن بَنِى اسرائِيلَ عَلى مِثْلِهِ فَآمَنَ وَ اسْتَكْبَرْتُمْ
and also the verse:
وَ مَن عِندَهُ عِلْمُ الْكِتبِ
have been sent down about him.
Then, he says: Ekrama and Hassan have denied this verse to be related to him, and they say: The verse has been revealed in Mecca while Abdullah has embraced Islam in Medina. Then he adds: Abu Omar says: The chapter of “Al-ahghaf, (the Sand-Hill),” which includes the verse “شَهِدَ شَاهِدٌ مِن بَنِى اسرائِيلَ ...” has also been revealed in Mecca so neither of the two statements is reliable. 
Ibn Athir Jazari says: When the people decided to kill Othman Abdullah bin Salam went to him and Othman asked him: ‘Why have you come to me?’ Abdullah said” I have come to help you. Othman said: ‘But if you go outside and to prevent the people from their decision is better for us than staying here – leave the house and prevent the people killing me.’
Abdullah bin Salam left the house, he stood in front of the people and said: ‘O people, in the time of the ignorance, was so and so and it was the Messenger of Allah who named me as Abdullah and there have been revealed some verses of the Qur’an concerning me, as:
وَ شَهِدَ شَاهِدٌ مِن بَنِى اسرائِيلَ عَلى مِثْلِهِ فَآمَنَ وَ اسْتَكْبَرْتُمْ...
‘… and a witness from among the Children of Israel testifies its likeness [with Torah], and believes in it, while you grow proud, (Qur’an: 46/10).’
And the blissful verse of: وَ مَن عِندَهُ عِلْمُ الْكِتبِ...
‘…and he who possesses the whole knowledge of the:
‘O people! The sword of Allah has been sheathed, and the angels have become quiet in this town of you – the town where the Messenger of Allah, Bless be to Him and his Descendants, arrived in for you. Fear Allah; fear Allah for killing this man. By Allah, if you kill him, all the angels who are in your neighborhood will turn away, and Allah will draw out the sheathed sword of His against you and then that sword will not be sheathed until the Day of Resurrection.’
However, the people shouted: ‘Let’s kill Othman, the Jew,’ and they killed him.
the foregoing subjects it is understood that Abdullah bin Salam considered himself to be the most learned on the Book [of Torah] and he himself knew the occasions of revelation of the verse, as Siyu:ti says: ‘Ibn Jarir and ibn Mardowiia have drawn it from Abd-ul-Malik that: Muhammad bin Yusuf bin Abdullah bin Salam, who is the grandson of Abdullah, says:
قَالَ عَبْدُ اللهِ بنُ سَلَامٍ: قَدْ أنزَلَ اللهُ فِىَّ القُرْآنَ: «قُلْ كَفَى بِاللَهِ شَهِيدًا بَيْنِى وَ بَيْنَكُمْ وَ مَن عِندَهُ عِلْمُ الْكِتب». 
‘Abdullah bin Salam said: For sure Allah has sent down in the Qur’an: Say, ‘Allah is sufficient as a Witness between you and I, and so is one who has the knowledge of the Book.’
And also Siyu:ti says: Ibn Mardowiia has related it from Azjondab that:
قال: جَاءَ عَبْدُ اللهِ بنُ سَلامٍ حَتَّى اخَذَ بِعِضادَتَى بابِ المَسْجِدِ ثُمَّ قالَ: أَنشُدُكُمْ بِاللهِ أ تَعْلَمُونَ انِّى انَا الَّذى انزِلَتْ فِيهِ: وَ مَن عِندَهُ عِلْمُ الكِتَبِ؟ قَالُوا: اللَّهُمَّ نَعَمْ. 
Therefore, Abdullah bin Salam considered himself, and his son as well as his grand son to be related to this verse.
As it was explained before, the Holiness Imam Bāqir rejected his son’s claim in front of Abdullah bin A’ta and stated: ‘By Allah, he is just lying, because the most learned on the Book is only Ali bin Abī Tālib.’ Some of them, like Mojahid, who have believe the occasions of the revelation of this verse is related to him are wrong; they are inventing it, it is not the statement of the Messenger of Allah.
And we already mentioned that Sha‘bi says: ‘Concerning Abdullah bin Salam, never has a verse of the Qur’an been sent down. And Saeed bin Jabir entirely rejected this argument and said: ‘This verse has been sent down in Mecca while Abdullah bin Salam was in Medina.’
Furthermore, when Mua‘wiyah bin Sofyan met Gheis bin Sa‘d in Medina, and Gheis asked him is this phrase وَ مَن عِندَهُ عِلْمُ الْكِتب about Ali bin Abī Tālib? Mua‘wiyah answered: ‘No, it is about Abdullah bin Salam.’ Gheis said: ‘But it means Ali,’ and he recited some verses of the Qur’an, such as:
إِنَّمَا أَنتَ مُنذِرٌ وَ لِكُلِّ قَوْمٍ هَادٍ،
‘… You are just a Warner; and for every nation is a guide; and
أَفَمَن كَانَ عَلَى بَيِّنَة مِن رَبِّهِ وَ يَتْلُوهُ شَاهِدٌ مِنهُ.
‘… What about one who stands upon a clear explanation from his Lord and to whom is a witness…?
And he said: the aim of ‘a guide’ in the first verse, and the meaning of ‘a witness’ in the second verse refer to Ali bin Abī Tālib, because the Messenger of Allah, Bless be to Him and his Descendants, assigned him as the Caliph on the Day of Ghadir, and he stated:
مَن كُنتُ مَولاهُ فَعَلىٌّ مَولاهُ.
‘Whoever I am Master to so is this Ali his Master.’
And he said:
أنْتَ بِمَنْزِلَة هَارُونَ مِن مُوسَى إلّا أنَّهُ لَا نَبِىِّ بَعْدى.
‘You are to me as Aaron to Moses, except that there is no messenger after me.’
Mua‘wiyah kept quiet by hearing his answer, and he did not dare to reject him. 
Thus, without slightest doubt, the meaning of “the learned on the Book” has nothing to do with Abdullah bin Salam.
Now, as he considered himself to be expert on the Torah and on the other hand, by coming across with the وَ مَن عِندَهُ عِلْمُ الْكِتب he has assumed that he deserved to have the verse coined for his position, or, God forbid it, while he knew the meaning of the ‘Book’ in this verse was the Qur’an, and meaning of the ‘the learned’ was no one but Ali bin Abī Tālib, he deliberately claimed to have this position. However, no matter what he thought, it was totally wrong as we explained it crystal clear.
Moreover, these fake narratives maybe invented by Bani Omayyad and the enemies of the Commander of the believers, Upon Him be Peace, as it became clear in the discussion of Mua‘wiyah with Gheis bin Sa‘d bin Ebada. It was because Mua‘wiyah always tried to tamper with the verses that revealed concerning the Commander of the believers, Upon Him be Peace, and in that way, to convey the virtues and priorities of Ali to the others. Therefore, he could not find a more suitable person than Abdullah bin Salam to set up against Ali bin Abī Tālib. It was clear that he could not nominate Abu Sofyan, or even himself who was fighting the Muslims until the victory of Mecca, on the other hand, Omar and Abu Bakr were not expert on the Book; therefore, the easiest way for altering the meaning of the Book from the Qur’an into Torah was through Abdullah bin Salam.
However, this alteration is not concealed from the sights of the scholars, from the beginning Sha‘bi, Hassan Basri, Saeed bin Jabir and even Ekrama, who were the enemies of Ali, knew that giving this title to Abdullah bin Salam was a big mistake. Nevertheless, for the ordinary people, who did not know that the chapter of Ar-Ra‘d was revealed in Mecca, and they did not know the biography of Abdullah bin Salam who was from Medina, and nor could they distinguish the verse to be from the Qur’an or the Torah, there was not any way better than this.
We clearly see that the enemies of the Household and the anti-Shiite, like ibn Teimeiia and alike, are insisting to set up Abdullah bin Salam against the rightful, Ali bin Abī Tālib – they do not want to give up even by seeing so many reasonable narratives in this respect. It is here that the truthfulness of this blissful verse in the chapter Ar-Ra‘d becomes clear:
أَفَمَن يَعْلَمُ أَنَّمَا أُنزِلَ إِلَيْكَ مِن رَبِّكَ الْحَقُ كَمَن هُوَ أَعْمَى إِنَّمَا يَتَذَكَّرُ أُولُوا الالْبب.
‘… What! Is one who knows what has been revealed to you from your Lord is the Truth, like someone who is blind? Only the sensible bear it in mind.
Now, it was time we brought the same phrases that Soleiman Ghandouzi Hanafi, along with some other scholars, who have related it in Yanabi Al-Mawadda from the Commander of the believers:
Some of the researchers say: Allah, the Blessed and Exalted, selected His Seal of the Messenger, the most noble of His messengers and the most respectable obedient worshipper by His great Generosity, everlasting knowledge and favour for His creatures as the Messenger. All this have occurred after He had taken the covenants of the previous messengers and the bygones people that to believe in Muhammad, Bless be to Him and his Descendants, and help him in his prophetic mission. Then, when the doors of mercy from the Creator were open and His guidance and bless showered on His beloved Messenger, Muhammad was informed to announce his situation to all the people of Quraish but first to Bani Hashim through this verse:
«وَ أَنذِرْ عَشِيرَتَكَ الاقْرَبِين»؛ وَ رَهْطَكَ المُخْلَصِينَ. 
It is quite reasonable that after the Messenger of Allah, one who is the most learned of everything, knowing the secrets and the facts of the Book of Allah must be one among the Bani Hashim, because comparing with the others in the Quraish tribe, one from Bani Hashim was closer to the Messenger. His embracing the Islam might be earlier than the others, to know the secrets of the prophetic mission and the case of the revelation right from the beginning. All the time, by all means to be at the service of the Messenger, his following the Messenger to be obvious, he should be aware of the activities of the Messenger and to be brought up away from the ignorance – he must be familiar with the manners and morale of the Generous Messenger.
Such conditions have not been noticed with anyone except with Ali bin Abī Tālib, Upon Him be Peace. However, Abdullah bin Salam had not embraced Islam until late after the migration of the Generous Messenger, (that is, a half of the course of the prophetic mission). And he did not know the cause of the revelation of the verses before the migration, nor did he know the facts of the verses revealed after the migration.
Salman Farsi, who had spent his long three-hundred and fifty years old life, on learning the secrets of the Bible and Torah, Psalms and other books about the previous messengers, and also investigating the Qur’an after his embracing the Islam in the Illuminated Medina was lacking of having the whole knowledge of Book – because he was short of the conditions that we mentioned already. So how could Abdullah bin Salam, who had not read the Bible and did not believe in it, and he was lacking of all the conditions we already mentioned to be expert on the Book?!
From the childhood of Ali bin Abī Tālib, the supporter of the religion, up to the beginning of the prophetic mission of the Messenger of Allah, whatever of the secrets and facts was occurred by the Commander of the believers, such as: his sermons:
سَلُونى قَبْلَ أَن تَفْقِدُونِى فَإنَّ بَيْنَ جَنْبَىَّ عُلُوماً كَالبِحارِ الزَّواخِر،
‘Ask me before losing me for indeed there is endless sea knowledge with me;’ and also whatever has occurred from his off spring, the Infallible Imams of Guidance, Upon Them be Peace, never has occurred by Abdullah bin Salim, so how can he be the learned on the Book?! 
مَا أَحَدٌ أعْلَمَ بِكِتابِ اللهِ بَعْدَ النَّبِىِّ مِن عَلِىِّ بنِ أبيطالِبٍ عليه السّلام وَ مِنَ الصّالِحِينَ مِن اوْلادِهِ عليهم السَّلَامِ. 
After the Messenger of Allah, never has been seen more learned than Ali bin Abī Tālib, Upon Him be Peace, and his righteous off spring on the Book of Allah.’
And Aasim bin Abi-an-Nojod quotes Abd-ur-Rahman bin Solma saying:
مَا رَأَيْتُ احَداً اقْرَأ مِن عَلِىِّ بنِ أَبِيطالِبٍ. 
‘I did not see anyone more learned than Ali bin Abī Tālib on the Qur’an’
And Abu Abd-ur-Rahman has quoted ibn Masoud saying:
لَوْ كُنتُ أعلَمُ احَداً أعْلَمَ بِكِتَابِ اللهِ مِنِّى لَاتَيْتُهُ.
‘If I knew someone who were more learned than I on the Book of Allah, I would go to him to learn [more].’
قالَ: فَقُلْتُ لَهُ: فَعَلِىُّ؟ قالَ: أ وَ لَمْ آتِهِ؟
Abd-ur-Rahman says, I said: ‘So go to Ali.’
He answered: ‘Have I not gone to him?’
According to what has been said so far, after the Messenger of Allah, the Commander of the believers is the most learned among the nation, and naturally the verse وَ مَن عِندَهُ عِلْمُ الْكِتب is related to him. And if someone else were the most learned at the time of revelation of the verse, then the verse would refer to him.
Now, it must be taken into consideration that why after Allah’s witnessing the Messenger has brought another witness – so what is the use of his witnessing in from of Allah’s?
Surely that witness must be decent and at the level of Allah’s, and it can be none but the Commander of the believers who knows the Qur’an by heart. The Qur’an is the aural words and he is the active words of Allah, he is the base for the Qur’an and the Qur’an indicates his being. These two are a unique fact which has been divided into two: aural and action, and are still connected together and can not be separated.
In fact, encountering the disbelievers, the Messenger of Allah apart from the aural witness and Allah’s written Qur’an which confirms his prophetic mission, brings another outward witness which is the centre of the Lights of Allah, His Names, the Essence of the Book. The reference for these two witnesses is the same statement of the Holiness which is accepted and said by both the Sunnite and the Shiite, he states:
إنّى تَارِكٌ فِيكُمُ الثَّقَلَيْنِ كِتَابَ اللهِ وَ عِتْرَتِى اهْلَ بَيْتِى وَ لَنْ يَقْتَرِفا حَتَى يَرِدا عَلَىَّ الحَوْضَ، مَا إن تَمَسَّكُتُمْ بِهِمَا لَنْ تَضِلُّوا بَعْدِى أَبَدا 
‘I leave with you two precious things: the Book of Allah and my Household; they will not be separated until they come to me by the Kow‘thar [river in Paradise].’
Now, this narrative can be the commentator of the foregoing verse, and it can be drawn from verse that the Imam and the Book are associated.
Let it be known that in some recitations of SHAZZ, this:
وَ مَن عِندَهُ عِلْمُ الْكِتبِ
Is recited as: وَ مَن عِندَهُ عِلمُ الكِتَاب according to what Siyu:ti is relating.  Off course this is the recitation of SHAZZ but the rest are not reliable, besides, in the point of view of the meaning it does not seem to be correct that Messenger’s statement ‘My witness is Allah,’ which has been known the Book by him. Although this meaning seems to be correct, as a sentence to attribute Allah to the disbelievers of the Quraish, it is weak.
Anyhow, it is put in the “Amali” of Sheikh Tousi that:
مَرَّ أميرُالمؤمنينَ بِمَلاءٍ فِيهِم سَلْمَانُ فَقالَ لَهُمْ سَلْمَانُ: قُومُوا فَخُذوا بِحُجْزَة هَذَا. فَوَ اللهِ لَا يُخْبِرُكُمْ بِسِرِّ نَبِيِّكُمْ غَيْرُهُ . 
The Commander of the believers, Upon Him be Peace, passed by a group that Salman was in. Salman told the others: ‘Come on, stand up and beseech that man. By Allah, no one can inform you of the secrets of your messengers except him.’
And in his commentary, Naq‘qash quotes ibn Abbas saying: ‘Ali bin Abī Tālib knew such knowledge that the Messenger of Allah had taught him, and the Messenger of Allah knew such knowledge that Allah had taught him; so the Messenger’s knowledge is the knowledge of Allah and Ali’s knowledge is the knowledge of the Messenger – and my knowledge is Ali’s knowledge. But, comparing my knowledge to Ali, the amount of my knowledge as well the knowledge of all companions of the Messenger is a tiny drop against seven seas.’ 
وَ مَن عِندَهُ عَلْمُ الكِتَابِ وَ عِلمُ مَا يكُونُ وَ مَا قَدْ كَانَ عِلماً مُكْتَمَا . 
‘He (Ali) is the one who owns all knowledge of the genesis, creation, whatever before them existed and what will come in the future.’
And Abu Moghatil bin Daee Alavi says:
وَ إنَّ عِندَكَ عِلْمَ الكَوْنِ أجْمَعَهُ مَا كَانَ مِن سَالِفٍ مِنْهُ وَ مؤتَنَفِ. 
‘Indeed it is gathered with you the whole knowledge of the Book and creation: whatever is passed and buried and whatever will take place in the long future.’
And Nasr bin Montasar says:
وَ مَن حَوى عِلْمِ الكِتَابِ كُلِّهُ عِلْمَ الَّذى يَأتِى وَ عِلْمَ مَا مَضَى. 
‘And he, (Ali), is the one who has the whole knowledge of the Book, and dominates it – the knowledge of the passed and the knowledge on the way coming.’
And the Commander of the believers, Upon Him be Peace, says:
و منها يعنى آل محمّد عليهم السّلام» هُم مَوْضِعُ سِرِّهِ، وَ لَجَأُ أمرِهِ، وَ عَيبَة عِلْمِهِ، وَ مَوئِلُ حُكْمِهِ، وَ كَهُوفُ كُتُبِهِ، وَ جِبالُ دينِهِ،
And those, that is, the Household of Muhammad, Upon Them be Peace, are the subject of His secret, and the safe haven with His command, and the flaw of His knowledge, and his habitat, and the caves of his Books, and the mountains of his religion,
And he continues:
لَا يُقاسُ بآلِ مُحَمَّدٍ عليهم السّلام مِن هَذهِ الامَّة أحَدٌ، وَ لَا يُسَوَّى بِهِمْ مَن جَرَتْ نِعمَتُهُمْ عَلَيْهِ أَبَداً. هُمُ أساسُ الدِّين، وَ عِمَادُ اليَقِينِ، الَيهِم يَفِىءُ الغالى، وَ بِهِمْ يَلْحَقُ التَّالى، وَ لَهُمْ خَصائِصُ حَقَّ الوِلَايَة، وَ فِيهِمْ الوَصِيَّة وَ الوِرَاثَة. 
‘There is none among this nation to be compared with the Household of Muhammad, Upon Them be Peace, and it is not their habit to lessen their blessing to anyone. They are the basis of the religion, the pillars of the certainty, for them is the highest position and right is on their side and they have the right characteristics of the guardians and successor-ships , and the wills and inheritance are with them.
المرام", page 357, the repetition of the second narrative, and he has
written the final part of this narrative in "مجمع البيان ", volume 3, page
301, also in "كافى", the book of " الحجه", volume 1, page 257.
 " ينابيع الموده", section 39, page 103.
"رجال"' برقى 'Rijal-e-Barqi' page 2.
قَالَ النَّبِى صَلّى الله عَليه و آلهِ و سلَّم: إنِّى تارِكٌ فيكُمُ الثَّقَلِينِ كِتابَ اللهِ وَ اهلَ بَيْتِى وَ أَنَّهُمَا لَن يَقْتَرِفا حَتَى يَرِدا عَلَّى الحَوْض.
The Messenger of Allah, Bless be to Him and his Descendants, '‘I leave with you two precious things: the Book of Allah and my Household; they will not be separated until they come to me by the Kow‘thar [river in Paradise]; and as long as you take resort in them, you will not get lost!’ And in the commentary of "الدّرّ المنثور", volume 2, page 7, he says:
و اخرج الترمذى و حسنه و ابن الانبارى فى المصاحف عن زيد بن ارقم رضى الله عنه قال: قال رسول الله صلّى الله عليه و آله و سلّم: انّى تارك فيكم ما ان تمسّكتم به لن تضلّوا بعدى، أحدهما أعظم من الاخر كتاب الله حبلٌ ممدودٌ من السماء إلى الارض و عترتى أهل بيتى و لن يفترقا حتّى يردا علىّ الحوض فانظروا كيف تخلفونى فيهما
And in "غاية المرام",
from the page 11 upward, he relates thirty-nine narratives by the Sunnite
and eighty-two narratives by the Shiite.