[Sahih Muslim: Book 1, Number 0161]

It is reported on the authority of Abu Huraira (Radi Allah Anhu) that the Messenger of Allah (sal-allahu- alleihi-wasallam ) observed: Avoid the seven noxious things. It was said (by the hearers): What are they, Messenger of Allah (sal-allahu- alleihi-wasallam)? He (the Holy Prophet (sal-allahu- alleihi-wasallam ) ) replied:
1. Associating anything with Allah,
2. Magic,
3. Killing of one whom God has declared inviolate without a just cause,
4. Consuming the property of an orphan,
5. And consuming of usury,
6. Turning back when the army advances,
7. And slandering chaste women who are believers, but unwary.