Matthew Poole and continuators on Numbers 25:3

3 And Israel joyned himself unto Baal-peor ▪ and the anger of the LORD was kindled against Israel.

The word implies a forsaking of God to whom they were and should have been joyned, and a turning to, embracing of strict conjunction with, and fervent affection, after this false God. Campare Hos. 9. 10. and 2 Cor. 6. 14.

Called Baal, by the name common to many false Gods, and especially to those that represented any of the heavenly bodies, and Peor, either from the hill Peor, where he was worshipped, Numb. 23. 28. or rather from a verb signifying to open and uncover, either because of the obscene posture in which possibly the Idol was s[illegible: 1+ letters]t. a[illegible: 1+ letters] Priapus was: or because of the filthiness which was exercised in his worship.

(i. e.) Discovered it self in a dreadful plague, Psal. 106. 29.