Numbers 25:16-18 - Vengeance Against The Midianites
16 And the LORD spake unto Moses, saying, 17 "Vex the Midianites and smite them, 18 for they have troubled you with their wiles with thee, which they have beguiled you, through Peor and through their sister Cozbi the daughter of a lord in Midian, which was slain in the day of the plague for Peor's sake."