Sahih Muslim Book 32, Hadith Number 6248.

Chapter : It is forbidden to commit oppression.

Jabir b. Abdullah reported that Allah’s Messenger (may peace be upon him) said: Be on your guard against committing oppression, for oppression is a darkness on the Day of Resurrection, and be on your guard against pettimindedness for pettimindedness destroyed those who were before you, as it incited them to shed blood and make lawful what was unlawful for them.