These, at various periods in the history of Israel, appeared in large numbers: Ahab had 'about four hundred' of them. 1 Kings 22:6 . Such are described as speaking "a vision of their own heart, and not out of the mouth of the Lord." Jeremiah 23:16 . There were three that opposed Jeremiah to his face — Hananiah, Ahab, and Zedekiah. Jeremiah 28:1; Jeremiah 29:21 . In the N.T. the Lord, early in His ministry, warned His hearers to beware of false prophets, Matthew 7:15; and in the church, the spirits are to be tried, for many false prophets have gone forth into the world. 1 John 4:1 . They were and are Satan's counterfeits of the prophets of God, and their purpose is, on the principle of imitation, to neutralise the word of God.