The Messenger of Allah (peace be upon him) said : "Allah Almighty has said : 'The son of Adam denied Me and he had no right to do so. And he reviled Me and he had no right to do so. As for his denying Me, it is his saying: He will not remake me as He made me at first (1) - and the initial creation [of him] is no easier for Me than remaking him. As for his reviling Me, it is his saying: Allah has taken to Himself a son, while I am the One, the Everlasting Refuge. I begot not nor was I begotten, and there is none comparable to Me." (1) i.e., bring me back to life after death.
It was related by al-Bukhari (also by an-Nasa'i).