because they bring trouble to you by their treachery with which they have deceived you in the matter of Peor, and in the matter of Cozbi, the daughter of a prince of Midian, their sister, who was killed on the day of the plague that happened as a result of Peor."

Look, these people through the counsel of Balaam caused the Israelites to act treacherously against the Lord in the matter of Peor -- which resulted in the plague among the community of the Lord!