سنن ابن ماجه

It was narrated from Thawban that the Prophet (ﷺ) said: “I certainly know people of my nation who will come on the Day of Resurrection with good deeds like the mountains of Tihamah, but Allah will make them like scattered dust.” Thawban said: “O Messenger of Allah, describe them to us and tell us more, so that we will not become of them unknowingly.” He said: “They are your brothers and from your race, worshipping at night as you do, but they will be people who, when they are alone, transgress the sacred limits of Allah.”