Prepare ye war - Rather, Sanctify ye war against her. War in ancient times was never undertaken without religions solemnities (see Deuteronomy 20:2 note). For some of these compare Ezekiel 21:21-23.
At noon - The mid-day heat is so great in the East as to be usually passed under shelter 2 Samuel 4:5; Song of Solomon 1:7. The morning-march of an army was made fasting, and was usually over by eight or nine. But so great is the impatience of the Chaldeans for the assault that they cry, “we will make the assault at noon!”
Woe unto us! - Or,
Alas for us! “for the day” has turned
For the evening shadows are lengthening!