On this verse, from Tafseer Noor ul Irfaan, by Allamah Ahmed Yaar Khan Naeemi:-
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Here, a negation is made only in regards to self understanding 1.e. he did not understand faith and Book through mere presumptions; negation is not of knowledge itself because prior to revelation the Holy Prophet (Allah’s blessings and peace be upon him) was already a worshipper, a devout ascetic, and a person of piety. In fact, the first revelation came when the Holy Prophet was in a state of seclusion (I'tikaaf) and worship of Allah Almighty. Also, at no stage in their lives were the Prophets unaware of Faith. Hazrat Isa (On whom be peace) at birth had said: And He has made me a Prophet''. You should also remember that when Jibreel (On whom be peace) brought the first revelation, the Holy Prophet knew with certainty that he was Jibreel and that whatever he was reciting was the Holy Qur’an and that he was sent by Allah Almighty. Therefore, the Holy Prophet did not enquire about his identity, nor regarding whether the speech was his own, or it was the Holy Qur’an. If the Holy Prophet did not have full knowledge about these things, then this verse would have remained doubtful to the Holy Prophet as harbouring a doubt about the Holy Qur’an is an act of infidelity. Says Allah Almighty: ''In it there is no place for doubt (S21: V2).
Going to Warqa bin Naufil was to bestow faith to him and not for the personal assurance and comfort of the Holy Prophet (Allah’s blessings and peace be upon him).
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