Numbers 25:3

25:3 When Israel joined themselves to Baal-peor, the anger of the Lord flared up against Israel.

Deuteronomy 4:46

4:46 in the Transjordan, in the valley opposite Beth Peor, in the land of King Sihon of the Amorites, who lived in Heshbon. (It is he whom Moses and the Israelites attacked after they came out of Egypt.

tn The verb is “yoked” to Baal-peor. The word is unusual, and may suggest the physical, ritual participation described below. It certainly shows that they acknowledge the reality of the local god.