سورة Al-Kahf ( The Cave ) - الآية 22

So the people will now say, “They are three, their dog is the fourth”; and some will say, “They are five, their dog is the sixth” – just blind guesses; and some will say, “They are seven, and their dog is the eighth”; proclaim (O dear Prophet Mohammed – peace and blessings be upon him), “My Lord well knows their number – no one knows them except a few”; therefore do not debate concerning them except what has occurred, and do not ask any of the People of the Book(s) anything concerning them.