Balak took Balaam to the top of Peor, that looks down on the desert.

Israel joined himself to Baal Peor: and the anger of Yahweh was kindled against Israel.

Moses said to the judges of Israel, "Everyone kill his men who have joined themselves to Baal Peor."

for they harassed you with their wiles, with which they have deceived you in the matter of Peor, and in the matter of Cozbi, the daughter of the prince of Midian, their sister, who was slain on the day of the plague in the matter of Peor."

Behold, these caused the children of Israel, through the counsel of Balaam, to commit trespass against Yahweh in the matter of Peor, and so the plague was among the congregation of Yahweh.