Forsaking the right way, they have gone astray. They have followed the way of Balaam, the son of Beor, who loved gain from wrongdoing, but was rebuked for his own transgression; a speechless donkey spoke with human voice and restrained the prophet's madness.
2 Peter 2:15-16
The story of Balaam (recorded in Numbers 22, 25) is one given unusual prominence in the later writings of the New Testament (see Jude 11 and Revelation 2:14). Balaam was undoubtedly a real prophet, but he succumbed to the temptation that filthy lucre presented, and greed of gain was his undoing. He deliberately turned from what he knew to be right from unworthy motives, and brought himself to a dishonoured end. Peter could scarcely have found a more apt illustration for his purpose of showing the ultimate doom of false teachers. Notice that he speaks of the 'madness' of the prophet in 16. It is a well-chosen word, for it is a satanic frenzy that grips men who 'sell themselves' to sin. They are no longer 'themselves', but possessed by an evil spirit that drives them mercilessly on their disastrous course: Indeed, this unholy 'drive' is a characteristic of false teachers; there is an evil fanaticism about them that is entirely alien to the good Spirit of God, and this should help us to identify them and discern between the true and the false. We are to try the spirits whether they be of God, and this is one way that we may do so.