Balaam

2 Peter 2:15 forsaking the right way, they went astray, having followed the way of Balaam the son of Beor, who loved the wages of wrongdoing.

Jude 1:11 Woe to them! For they went in the way of Cain, and ran riotously in the error of Balaam for hire, and perished in Korah’s rebellion.

Revelation 2:14 But I have a few things against you, because you have there some who hold the teaching of Balaam, who taught Balak to throw a stumbling block before the children of Israel, to eat things sacrificed to idols, and to commit sexual immorality.

For God speaking through Balaam, see Numbers 23:5ff