Sahih Muslim
The Book on Government (Kitab Al-Imara)
Book Number: 020 / Hadith Number: 4492
It has been reported on the authority of Abu Dharr that the Messenger of of Allah (may peace be upon him) said: Abu Dharr, I find that thou art weak and I like for thee what I like for myself. Do not rule over (even) two persons and do not manage the property of an orphan.