Jeremiah 36:6

We do not read that Jeremiah was a prisoner in the fourth year of Jehoiakim, and therefore it is very uncertainly guessed in what sense he here saith he was shut up. Some think Jehoiakim had imprisoned him, or at least restrained him to his house, though we do not read of it. Others think he restrained himself; but in what sense he was shut up is not certain; that he was so is certain. He knew that God had not commanded his prophecies to be written for any other end, but that the people might have them recalled to their memories: he being not in a capacity himself at present to speak any thing to the people in so public a place, sendeth Baruch to do it in his stead, choosing for it a day of public fast; not the day of the yearly fast mentioned Leviticus 23:27, but on a fast day (of which we shall read more Jeremiah 36:9) proclaimed by Jehoiakim, probably to avert the vengeance hanging over them from the Chaldeans, or rather from the drought. It was, undoubtedly, because of the concourse of people which the prophet knew would that day be in the temple that he chose that day, when some would be present from all parts of Judah.