Sahih Muslim
The Book of Transactions (Kitab Al-Buyu)
Book Number: 010 / Hadith Number: 3619
Abu Huraira reported Allah's Messenger (may peace be upon him) as saying: A Muslim should not purchase (in opposition) to his brother. This hadith has been narrated on the authority of Abu Huraira through another chain of transmitters but with a slight change of words.