Muwatta Malik, Book 49, Hadith 18 (USC-MSA)

Yahya related to me from Malik from Abu Hazim ibn Dinar from Sahl ibn Sad al-Ansari that the Messenger of Allah, may Allah bless him and grant him peace, was brought a drink and he drank some of it. There was a boy at his right and some old men on his left. He said to the boy, "Will you give me permission to give it to these people?" The boy said, "No, Messenger of Allah, I will not prefer anyone to get my portion from you." He said, "So the Messenger of Allah, may Allah bless him and grant him peace, placed it in his hand."

وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ أَبِي حَازِمِ بْنِ دِينَارٍ، عَنْ سَهْلِ بْنِ سَعْدٍ الأَنْصَارِيِّ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم أُتِيَ بِشَرَابٍ فَشَرِبَ مِنْهُ وَعَنْ يَمِينِهِ غُلاَمٌ وَعَنْ يَسَارِهِ الأَشْيَاخُ فَقَالَ لِلْغُلاَمِ ‏ "‏ أَتَأْذَنُ لِي أَنْ أُعْطِيَ هَؤُلاَءِ ‏" ‏ ‏.‏ فَقَالَ الْغُلاَمُ لاَ وَاللَّهِ يَا رَسُولَ اللَّهِ لاَ أُوثِرُ بِنَصِيبِي مِنْكَ أَحَدًا ‏.‏ قَالَ فَتَلَّهُ رَسُولُ اللَّهِ صلى الله عليه وسلم فِي يَدِهِ ‏.‏

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also referenced under: Book 49, Hadith 1691 (In-Book)