What was the religion of the People of the Cave?

The Companions of the Cave were young, faithful monotheists who believed in Allah the Almighty. They isolated themselves from their polytheistic people because of their polytheism, as stated in Allah's (the Most High) saying: "Indeed, they were youths who believed in their Lord, and We increased them in guidance," and His (the Most High) saying: "And when you have withdrawn from them and what they worship other than Allah, then seek refuge in the cave." Other details about their religion are not supported by evidence from the Quran or Sunnah.