Abu Ahwas reported: We were in the house of Abu Musa along with some of the companions of 'Abdullah and they were looking at the Holy Book. 'Abdullah stood up, whereupon Abu Mas'ud said: I do not know whether Allah's Messenger, (ﷺ) has left after him one having a better knowledge (of Islam) than the man who is standing. Abu Musa said: If you say this, that is correct, because he had been present when we had been absent and he was permitted when we were detained.
Hadith Referenceصحيح مسلم / كتاب فضائل الصحابة / 2461
'Abdullah reported: By Him besides Whom there is no god, there is no chapter in the Book of Allah about which I do not know as to where it was revealed and there is no verse about which I do not know in what context it was revealed, and if I were to know of one having a better understanding of the Book of Allah than I (and I could reach him) on the back of the mule, I would have definitely gone to him on camel's back.
Hadith Referenceصحيح مسلم / كتاب فضائل الصحابة / 2463