Matthew Poole and continuators on 2 Peter 2:16

16 But was rebuked for his iniquity, The dumb ass speaking with mans voice, forbad the madness of the propher .

Not only by the Angel's speaking to him, but by the Ass's, as follows.

Not in express words that we read of, but the Ass's speaking with human Voice, discerning the Angel before Balam did, and going back, when he, carried out by the power of his Covetousness, would needs go forward, were so prodig[illegible: 1 letter]ous things as might sufficiently convince him of his Sin, in going to Balak, contrary to God's Command at first given him; and it was no small Dishonour put upon him, that he who would not hearken to God, should have an Ass for his Teacher.

In going against God's Command, and to curse those who, God had told him, were blessed. Object. Balaam had leave given him to go with Balak's Messengers, Num. 22.20. and refused Balak's Offers, v. 18. Ans. Balaam did not contemn the Gifts offered, but had a Desire after them, as appears by his enquiring of God the second time, v. 19. tho God had fully revealed his Will to him before, v. 12. 2ly, God [illegible: 1 letter]ad him go, that he might bless the People, v. 12. compare with 20. whereas he went not out of a respect to God's Answer, but out of a covetous Mind, and a Desire to curse Israel, as appears by Iosh. 24.9, 10. and by the cursed Counsel he gave, Num. 25.1. compare with 31.16. and Rev. 2.14.

Balaam is called a Prophet here, either, 1. because he pretended to be so: thus the false Prophets are sometimes called absolutely▪ Prophets, Ier. 6.13. and 26.7, 8.11. Or, 2ly. because he really was a Prophet, though a wicked and covetous one; for he enquired of God, and had Answers from him, Num. 6.22. & 8.9, 10, 18, 19. and Moses saies expresly, that the Lord put a world in Balaam's Mouth, ch. 23.5, 16. and that Prophecy concerning the Messiah, Num. 24.17. could not but be of God; yet it is probable, that Balaam, out of Covetousness, might sometimes use Divination; nay, it is plain in some cases he did, Num. 24.1.