His Whispering Means Nothing
Question :
At times, Shaytan whispers to me and asks: "Who created this?" He continues to ask similar questions until he says, "And who created Allâh Almighty?" What should I do about these suggestions of his?
Answer:
These evil whispers of his have no effect on you. The Prophet said that Shaytan comes to man and says, "Who created such and such?" until he says, "Who created Allah?" Then the Messenger of Allah informed us of a potent remedy: to seek refuge in Allâh Almighty from the despised Shaytan. So if you are stricken by this and begin to think in such manner, then say, "I seek refuge in Allah from the despised Shaytan." Then be finished with the matter and it will go away completely by the permission of Allah.
Source:
Ibn 'Uthaimin
Fatawa Islamiyah, Vol. 8 Page 312