Hadith 759

Anas (May Allah be pleased with him) reported: Milk mixed with water was brought to the Messenger of Allah (PBUH). On his right side was sitting a bedouin and on his left was sitting Abu Bakr (May Allah be pleased with him). He (PBUH) drank from it and handed the rest to the bedouin saying, "One who is on the right has preference, then again the one who is on the right."

[Al-Bukhari and Muslim].