Sahih Muslim Book 26, Hadith Number 5540.

Chapter : Kahanat (Divination) is prohibited and it is forbidden to go to Kahin.

Safiyya reported from some of the wives of Allah’s Apostle (may peace be upon him) Allah’s Apostle (may peace be upon him) having said: He who visits a diviner (‘Arraf) and asks him about anything, his prayers extending to forty nights will not be accepted.