Numbers 25:3-5

³And Israel joined himself to Baal-Peor; and the anger of Jehovah was kindled against Israel.

⁴And Jehovah said to Moses, Take all the heads of the people, and hang them up to Jehovah before the sun, that the fierce anger of Jehovah may be turned away from Israel.

⁵And Moses said to the judges of Israel, Slay every one his men that have joined themselves to Baal-Peor.