Sayyiduna Rabah bin al-Rabi' (may Allah be pleased with him) said: We went on a military expedition with the Messenger of Allah (peace and blessings be upon him), and he (peace and blessings be upon him) had given every three of us one camel, on which two would ride while one drove it; in the open plains we rode, and in the mountains we led it on foot. The Messenger of Allah (peace and blessings be upon him) passed by me while I was walking and said: "Rabah! I see you walking." I said: I have only just dismounted, and these two companions of mine are riding. He (peace and blessings be upon him) went on and passed by my two companions, and they made their camel kneel and dismounted from it. When I reached them, they said: Ride on the front of this camel and stay on it until we return, and my companion and I will take turns riding. I asked: Why? They said that the Messenger of Allah (peace and blessings be upon him) had said: "You two have a righteous companion, so treat him well."
Hadith Referenceالمعجم الكبير للطبراني / باب الراء / 4608