It is narrated from Sayyiduna Ma'mar bin Abdullah (may Allah be pleased with him); he said: I used to saddle the mount of the Messenger of Allah (peace and blessings be upon him). The Prophet (peace and blessings be upon him) said: "O Ma'mar!" He said: "Last night I felt some looseness in my saddle girths." I said: O Messenger of Allah, I fastened them just as I always fasten them, but the one who envies me this closeness wants me to be replaced. He (peace and blessings be upon him) said: "I will not do that." When the Messenger of Allah (peace and blessings be upon him) had finished his Hajj, he (peace and blessings be upon him) ordered me, so I took the razor and sharpened it. The Messenger of Allah (peace and blessings be upon him) said: "O Ma'mar! The Messenger of Allah (peace and blessings be upon him) has given you access to the lobe of his ear while the razor is in your hand." I said: O Messenger of Allah, I regard this as a favour and grace from you (peace and blessings be upon him) upon me. He (peace and blessings be upon him) said: "Yes, indeed." (The narrator said:) So increase in that (gratitude).
Hadith Referenceالمعجم الكبير للطبراني / باب الميم / 18220