Muwatta Imam Malik (Riwayat Ibn al-Qasim)

And with this same chain (it is narrated from Sayyiduna Sahl bin Sa’d, may Allah be pleased with him) that a drink (i.e., milk) was brought to the Prophet, peace and blessings be upon him, and he drank from it. On his right was a boy and on his left were elderly people, so he said to the boy: If you permit me, shall I give this (remaining portion) to these (elderly) people? The boy said: No, O Messenger of Allah! By Allah, I will not give preference to anyone over your leftover. So the Messenger of Allah, peace and blessings be upon him, placed it in his hand.