Albert Barnes Commentary Jeremiah 27:13-15

"Why will ye die, thou and thy people, by the sword, by the famine, and by the pestilence, as Jehovah hath spoken concerning the nation that will not serve the king of Babylon? And hearken not unto the words of the prophets that speak unto you, saying, Ye shall not serve the king of Babylon; for they prophesy a lie unto you. For I have not sent them, saith Jehovah, but they prophesy falsely in my name; that I may drive you out, and that ye may perish, ye, and the prophets that prophesy unto you." — Jeremiah 27:13-15 (ASV)

Zedekiah was restless under the Babylonian yoke, and the false prophets found him all too ready to listen. He is addressed in the plural because his feelings were fully shared by the majority of the state officials and by the people.