'Treacherously' in the Bible

"Instruct the Israelis that whenever a man or woman does something contained in the list of the sins of man, thereby acting treacherously against the LORD, then that person stands guilty.

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!