Numbers 25:16 - 25:18
16 Then Yahweh spoke to Moses, saying, 17 “Be hostile to the Midianites and strike them, 18 for they have been hostile to you with their deceptive tricks, with which they have deceived you in the affair of Peor and in the affair of Cozbi, the daughter of the leader of Midian, their sister who was slain on the day of the plague because of Peor.”