Jeremiah 38:2 - Ellicott's Commentary On The Whole Bible

Thus saith the Lord. — The words carry us back to Jeremiah 21:9, and in any chronological arrangement of the book the one chapter would follow the other. It is obvious that to all who did not recognise the divine mission of the prophet, words like those which he had then spoken would seem to come from the lips of a traitor. Desertion to the enemy was represented as the only way of safety, and this was the counsel given to those who were defending the city of their fathers against an alien invader. What made it appear worse was that the prophet himself had been caught in an act which, though he denied the charge, might not unnaturally seem like an act of treacherous desertion.