وعن أنس رضى الله عنه
أن رسول الله صلى الله عليه وسلم أتى بلبن قد شيب بماء، وعن يمينه أعرابي، وعن يساره أبو بكر رضى الله عنه، فشرب، ثم أعطى الأعرابي وقال: «الأيمن فالأيمن»
Milk mixed with water was brought to the Messenger of Allah (sallallahu alayhi wa sallam). On his right side was sitting a bedouin and on his left was sitting Abu Bakr (radiyallahu anhu). He (sallallahu alayhi wa sallam) 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.”.
Riyad as-Salihin 759, Book 3, The Book About the Etiquette of Eating, Hadith 33. 1 min read