sahl b. sa'd, with whom allah is pleased, reported:

"a drink was brought to the prophet, may allah exalt his mention, and he drank from it. on his right side there was a young boy and on his left side were elderly men. he asked the young boy: 'do you mind if i give the drink to them?' the young boy said: 'o prophet of allah! by allah! i would not prefer anyone to drink from the place you drank. this is my fair share [due to sitting to your right].’ the messenger of allah, may allah exalt his mention, handed the boy the drink."  (bukhari #2319)