Matthew Poole and continuators on Psalms 106:28

28. They joyned themselves also unto Baal-peor, and ate the sacrifices of the dead .

To wit, in Worship, whereby they had an union and communion with him, as Gods People have with God in acts of his Worship. And this phrase seems also to note their Carnal Copulation with the Daughters of Moab in the Temple, or to the Honour of Baal-Peor.

Which were offered to Idols, which he calls dead, in opposition to the true and living God, and by way of contempt, and to note the sottishness of Idolaters who worshipped lifeless things, as stocks and stones or dead Men. And some learned men conceive that this is spoken with particular regard to Baal-Peor, or the Lord of Peor, a place so called, who had been a Person of great eminency in those parts, and therefore was Worshipped according to the custom of the Heathens, after his Death, by Sacrifices and Feasts appointed for his Honour and Memory.

Marginal references: Num. 25. 2, 3. & 31. 16. Rev. 2. 14.