A recurring characteristic of the false prophet is that they often are found in the employment of the powerful and that they are careful to speak pleasing, positive and flattering words to their employers. Jeremiah condemned the false prophets who where always saying "Peace, peace!" When there was no peace. (Jer. 6:14; 8:11).The prophets preached a popular but false message: There would be victory against Babylon( Jer28:1-17) Jeremiah said , "The prophets prophesy falsely... and my people love to have it so. (Jer5:31.
In the Bible false prophets fell into 3 general catigories: (1) those who worshipped false gods and served idols; (2) those who falsely claimed to recieve messages from the Lord; and (3) those who wandered from the truth and ceased to be true prophets. All of which could result in being stoned to death.
-paraphrased Nelson's Bible Dictionary.