John Calvin on Jeremiah 17:20

He then adds, Thou shalt say to them, Hear the word of Jehovah, ye kings of Judah, and let all the people hear, and let all the citizens of Jerusalem hear, who enter in at these gates. The Prophet was commanded to begin with the king himself, who ought to have repressed so great a licentiousness. It was therefore an intolerable indifference in the king silently to bear this contempt of religion, especially in a matter so easy and so evident; for he could not have pretended that he was unacquainted with it: it was indeed the same as though the Jews intended to triumph against God, and to shew that his law was deemed of no value. Hence the profanation of the Sabbath was a proof of their shamelessness, as they thereby shewed that they cared nothing either for God or for his law. We shall hereafter see how great that wickedness was; but; I shall defer the subject, as I cannot now discuss it at large, and a more convenient opportunity will offer itself.