The Book Pertaining to the Merits of the Companions (Allah Be Pleased With Them) of the Holy Prophet (May Peace Be Upon Him) (Kitab Al-Fada'il Al-Sahabah)
Muslim :: Book 31 : Hadith 6174
Abu Dharr reported Allah's Messenger (may peace be upon him) as saying: You would soon conquer Egypt and that is a land which is known (as the land of al-qirat). So when you conquer it, treat its inhabitants well. For there lies upon you the responsibility because of blood-tie or relationship of marriage (with them). And when you see two persons falling into dispute amongst themselves for the space of a brick, than get out of that. He (Abu Dharr) said: I saw Abd al-Rahman b. Shurahbil b. Hasana and his brother Rabi'a disputing with one another for the space of a brick. So I left that (land).