4, 5. The invading soldiers encourage one another to the attack on Jerusalem.
      Prepare--literally, "Sanctify" war, that is, Proclaim it formally with solemn rites; the invasion was solemnly ordered by God (compare Isa 13:3).
      at noon--the hottest part of the day when attacks were rarely made (Jer 15:8; 20:16). Even at this time they wished to attack, such is their eagerness.
      Woe unto us--The words of the invaders, mourning the approach of night which would suspend their hostile operations; still, even in spite of the darkness, at night they renew the attack (Jer 6:5).

JFB.