From Sahih Muslim (Hadith 5289):
Anas b. Malik reported that there was brought to Allah's Messenger (ﷺ) a cup of milk mixed with water, while there was on his right a desert Arab and on his left Abu Bakr. He (the Holy Prophet) drank; he then gave it to the desert Arab and said:(Give to one) who is on the right, then again who is on the right
Reference: Muslim 5289