Hazrat Abu Bakr Al-A’yan (rahimahullah) was a great Muhaddith who was the Ustaad of leading Muhadditheen, the likes of Imaam Muslim (rahimahullah) and Imaam Abu Dawood (rahimahullah). During his youth, when he was seventeen years old, he was blessed with the honor of acquiring Ahaadith from Imaam Bukhaari (rahimahullah), who was also young at the time.
He mentions, “We wrote Ahaadith from Imaam Bukhaari (rahimahullah) at the door of Muhammed bin Yusuf Al-Firyaabi. At that time, Imaam Bukhaari (rahimahullah) did not have any hair on his face (i.e. on account of his tender age, his beard had not yet appeared).” (Siyar A’laamin Nubalaa 12/401)
Imaam Bukhaari (rahimahullah) was so fortunate that Allah Ta‘ala blessed him with universal acceptance. He was granted such an esteemed position in the science of Hadith that even his Ustaads attested to his proficiency and mastery in the science of Hadith.
It is reported that the great Ustaad of Imaam Bukhaari (rahimahullah), Hazrat Muhammed bin Salaam Al-Bikandi (rahimahullah), who was a student of Hazrat Abdullah bin Mubaarak (rahimahullah), had requested Imaam Bukhaari (rahimahullah) saying, “Look through my kitaabs, and if you find any mistake in them, then mark the mistake and inform me so that I will not narrate the mistake.” Accordingly, Imaam Bukhaari (rahimahullah) did as his Ustaad instructed.
Observing the great respect which Muhammed bin Salaam (rahimahullah) showed to Imaam Bukhaari (rahimahullah), a person asked Muhammed bin Salaam (rahimahullah), “Who is this youngster?” Muhammed bin Salaam (rahimahullah) replied, “He is a person who is unparalleled in his expertise in the field of Hadith.” (Tahzeeb-ul-Kamaal 24/459)