Musnad Abi Ya'la 5311 — he said: I was a young boy and used to graze

It is narrated from Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) that he said: "I was a young boy and used to graze the goats of Uqbah bin Abi Mu'ayt, when the Prophet (peace and blessings be upon him) and Sayyiduna Abu Bakr (may Allah be pleased with him) came by (while leaving Makkah), having escaped from the polytheists. They asked: 'O boy, do you have any milk that you can give us to drink?' I said: Yes, I do, but I am a trustee, and I cannot give the two of you milk to drink (without the owner's permission). The Prophet (peace and blessings be upon him) said: 'Do you have a young she-goat that no male has yet mated with (that is, one that has not yet conceived and gives no milk)?' I said: Yes. So I brought it to him (peace and blessings be upon him), and the Messenger of Allah (peace and blessings be upon him) took hold of it, passed his hand over its udder and supplicated, and the milk began to flow abundantly. Sayyiduna Abu Bakr (may Allah be pleased with him) brought a deep, bowl-like hollow stone, and he (peace and blessings be upon him) milked into it, then drank himself; Sayyiduna Abu Bakr (may Allah be pleased with him) also drank, and I drank too. Then he (peace and blessings be upon him) said to the udder: 'Shrink,' and it became as it was (dry, as before). After that I came to him (peace and blessings be upon him) and said: O Messenger of Allah (peace and blessings be upon him), teach me something of this speech, that is, of this Qur'an. He (peace and blessings be upon him) said: 'Indeed, you are a well-taught (well-mannered) boy.' So he (peace and blessings be upon him) taught me, and I took seventy surahs directly from his blessed mouth, in which no one can dispute or rival me."