Albert Barnes Commentary 2 Peter 2:16

"but he was rebuked for his own transgression: a dumb ass spake with man`s voice and stayed the madness of the prophet." — 2 Peter 2:16 (ASV)

But was rebuked for his iniquity. The object of Peter in this seems to be to show that God employed the very extraordinary means of causing the ass on which he rode to speak, because his iniquity was so monstrous. The guilt of thus debasing his high office, and going out to curse the people of God—a people who had done him no wrong and given no occasion for his malediction—was so extraordinary, that means as extraordinary were proper to express it. If God employed means so extraordinary to rebuke his depravity, it was to be expected that in some appropriate way He would express His view of the wickedness of those who resembled him.

The dumb ass, speaking with man's voice (Numbers 22:28). God seems to have intended that both Balaam and Balak should be convinced that the children of Israel were His people; and so important was it that this conviction should rest fully on the minds of the nations through whom they passed, that He would not allow even a pretended prophet to use his influence to curse them.

He intended that all that influence should be in favor of the cause of truth, thus providing a striking instance of the use which He often makes of wicked men. To convince Balaam of the error of his course, to make him aware that God was an observer of his conduct, and to induce him to utter only what He should direct, nothing would be better suited than this miracle.

The very animal on which he rode, dumb and naturally stupid, was made to utter a reproof—a reproof as directly from heaven as if the stones had cried out beneath his feet, or the trees of the wood had uttered the language of remonstrance. Concerning the nature of the miracle referred to here, it may be noted:

1. That it was as easy for God to perform this miracle as any other; and
2. That it was a miracle that would be as likely to be effective, and to serve the purpose, as any other. No one can show that it could not have occurred; and the occasion was one in which some decided rebuke, in language beyond that of conscience, was necessary.

Forbad the madness of the prophet. That is, the mad or perverse design of the prophet. The word here rendered madness properly means a departure from a right mind. It is not found elsewhere in the New Testament. It is used here to denote that Balaam was engaged in an undertaking which indicated a headstrong disposition, acting contrary to reason and sound judgment. He was so under the influence of avarice and ambition that his sound judgment was blinded, and he acted like a madman.

He indeed knew what was right and had professed an intention to do what was right, but he did not allow that to control him. For the sake of gain, however, he went against his own firm conviction and against what he knew to be the will of God. He was so mad or infatuated that he allowed neither reason, nor conscience, nor the will of God, to control him.