The Messenger of Allah ﷺ said, "People will keep on questioning one another until they say, 'This is Allah, the Creator of everything, but who created Allah?'"
قال رسول الله ﷺ: لن يبرح الناس يتساءلون حتى يقولوا: هذا الله خالق كل شيء، فمن خلق الله؟
Bukhari narrated it in the Book of Holding Fast (7296), from Hasan bin Sabbah, from Shababa, from Waraqa, from Abdullah bin Abdul-Rahman, who said, I heard Anas bin Malik say, and he related it.Muslim narrated it in the Book of Faith through another route, from Mukhtar bin Fulful, from Anas, with similar wording.