Jamieson, Fausset and Brown on Jeremiah 37:3

3. Zedekiah ... sent--fearing lest, in the event of the Chaldeans overcoming Pharaoh-hophra, they should return to besiege Jerusalem. See on Jr 21:1; that chapter chronologically comes in between the thirty-seventh and thirty-eighth chapter. The message of the king to Jeremiah here in the thirty-seventh chapter is, however, somewhat earlier than that in the twenty-first chapter; here it is while the issue between the Chaldeans and Pharaoh was undecided; there it is when, after the repulse of Pharaoh, the Chaldeans were again advancing against Jerusalem; hence, while Zephaniah is named in both embassies, Jehucal accompanies him here, Pashur there. But, as Pashur and Jehucal are both mentioned in Jr 38:1, 2, as hearing Jeremiah's reply, which is identical with that in Jr 21:9, it is probable the two messages followed one another at a short interval; that in this Jr 37:3, and the answer, Jr 37:7-10, being the earlier of the two.

Zephaniah--an abettor of rebellion against God (Jr 29:25), though less virulent than many (Jr 29:29), punished accordingly (Jr 52:24-27).