Abu Dawud Book 11, Hadith Number 2862.
Chapter : On execution of wills.
Narated By Abu Dharr : The Apostle of Allah (PBUH) said to me: Abu Dharr, I see you weak, and I like for you what I like for myself. Do not be a leader of two (persons), and do not be a guardian of the property of an orphan.
Abu Dawud said: This has been narrated only by the people of Egypt.