Both the prophets and the priests were profane. Even in Jehovah's house, the temple, their wickedness had been found by Him (v. 11). To be profane is to be worldly. Instead of being sanctified, separated unto God as a holy people, they were profane.
The prophets of Samaria prophesied by Baal and led Jehovah's people Israel astray—an offensive thing (v. 13). In the prophets of Jerusalem Jehovah saw a horrible thing: the committing of adultery and walking in falsehood. They strengthened the hands of the evildoers so that none turned from their wickedness. All of them had become to Him like Sodom and her inhabitants like Gomorrah (v. 14). Their profaneness had gone forth from them in Jerusalem into all the land (v. 15b).
The prophets prophesied to lead the kings with the people to vanity (v. 16a). Here vanity means idols. They also spoke a vision of their own heart, not out of the mouth of Jehovah (v. 16b). They were continually saying to those who despised Jehovah, "Jehovah has spoken, You will have peace." To everyone who walked in the stubbornness of his own heart they were saying, "Evil will not come upon you" (v. 17). They told the people that there would be no calamities and that no bad things would happen to them. How evil were the prophets of Judah!
Jehovah did not send these prophets, but they ran forth. He did not speak to them, yet they prophesied (v. 21). If they had stood in Jehovah's council and had caused the people to hear His words, they would have turned them from their evil way and from the wickedness of their deeds (v. 22).