Sahih Muslim Book 31, Hadith Number 6111.

Chapter : Pertaining to the good which lies in accompanying the Ansar (Allah be pleased with them).

Anas b. Malik reported: I set out along with Jabrir b. ‘Abdullah al-Bajali on a journey and he used to serve me. I said to him: Don’t do that. Thereupon he said: I have seen Ansar doing this with Allah’s Messenger (may peace be upon him). I swore by Allah whenever I accompany any one of the Ansar, I would serve him and Ibn Muthanni, and Ibn Bashshir made this addition in their narrations: Jarir was older than Anas, and Ibn Bashshir said: He was of a more advanced age as compared with Anas. Allah’s Apostle (may peace be upon him) invoked blessings for the tribes of Ghifar and Aslam.