(Al-Hijr) 15 : 62
قَالَ إِنَّكُمْ قَوْمٌ مُنْكَرُونَ
He said: "Indeed, you are a forbidden people".
Angels have come to Looth in the form of the handsome youths. So Looth feared that his transgressed/Mujirim people will sodomize his guests as explained in verses 11: 77-83. That is why Looth who is unaware of the guests said that they wouldn’t have come to his place.