Sahih Muslim Book 1, Hadith Number 244.

Chapter : Pertaining to evil suggestion or prompting in faith and what should be said when it occurs to the mind of a man.

It is narrated on the authority of Abu Huraira that the Messenger of Allah may peace be upon him) observed: The Satan comes to everyone of you and says: Who created this and that? till he questions: Who created your Lord? When he comes to that, one should seek refuge in Allah and keep away (from such idle thoughts).