Sahih Bukhari Volume 3, Book 47, Hadith Number 776.

Narated By Shal bin Sad : A drink (of milk and water) was brought to Allah’s Apostle while a boy was sitting on his right side and old men were sitting on his left side. He asked the boy, “Will you allow me to give it to these (people)?” The boy said, “No, by Allah, I will not allow anyone to take my right from you.” Then the Prophet put the bowl in the boy’s hand.