Sahih Bukhari

Narrated Sahl bin Sa`d:Allah's Messenger (ﷺ) was offered something to drink. He drank of it while on his right was a boy and on his left were some elderly people. He said to the boy, ""May I give these (elderly) people first?"" The boy said, ""By Allah, O Allah's Messenger (ﷺ)! I will not give up my share from you to somebody else."" On that Allah's Messenger (ﷺ) placed the cup in the hand of that boy