Jeremiah 6:4 - Ellicott's Commentary On The Whole Bible

Prepare ye war. — Literally, Sanctify. The opening of the battle was accompanied by sacrifices, divinations, and prayers. Compare Deuteronomy 20:1-3 for the practice of the Israelites, and Ezekiel 21:20-22 for that of the Chaldæans, which was, of course, present to Jeremiah’s mind. The cry thus given with dramatic force comes from the soldiers of the invading army impatient for the fight. They are so eager that, instead of resting at noon, as usual, for their mid-day meal, they would fain press on for the assault. Their orders are against this, and, as the shadows lengthen, they raise their cry of complaint, “Alas for us, the day declines...” Then, impatient still, unwilling to wait, as their commanders bid them, for an attack at day-break, they shout, “Let us go by night.”