“O people, by Allâh I have visited kings. I went to Caesar, Chosroes and the Negus, but by Allâh I never saw a king whose companions venerated him as much as the companions of Muhammad venerated Muhammad (peace and blessings of Allâh be upon him). By Allâh, whenever he spat it never fell on the ground, it fell into into the hand of one his companions, then they wiped their faces and skins with it. If he instructed them to do something, they would hasten to do as he commanded. When he did wudû’, they would almost fight over his water. When he spoke they would lower their voices in his presence; and they did not stare at him out of respect for him.”
-al-Bukhârî, 3/178, no. 2731, 2732; al-Fath, 5/388.