John Gill Bible Commentary

The prophet which prophesieth of peace,.... Of prosperity, of good things, as Hananiah did, and which are always acceptable to men; and such a prophet is agreeable to them: when the word of the Lord shall come to pass; when the prophecy of good things, which he delivers in the name of the Lord, shall be filled: then shall the prophet be known that the Lord hath truly sent him; and not till then; it is the event that must make it manifest: in the other case it may be in a good measure known before it comes to pass, and, whether it comes to pass or not, that a prophet is a true prophet; because his prophecies are agreeable to the word and the declared will of God; contain evils threatened on account of sin, and in order to bring men to repentance, which must needs be right; and besides, they have no interest of their own to serve, but run contrary to the stream of the people, and are exposed to their rage and censure: whereas, a man that prophesies of peace, he is more to be suspected of flattering the people, and of prophesying out of his own heart; and nothing but the event can show him a true prophet; which if he delivers with a proviso, that the people do not do that which is evil in the sight of God, to provoke him to deny them the promised good, is always certainly fulfilled; and if it is not, then he appears manifestly a false prophet.