quiet. secure.
cut down. cut down (like dry stubble).
when he, &c. Reference to Pentateuch (Exodus 12:12). Compare Isaiah 8:8; Daniel 11:10.
-12 Though, &c. = And [now,. Judah], &c. Through not seeing the Structure and the change of subject at "-12-14", modern critics say "the first part of this verse is certainly more or less corrupt"; and they alter the Hebrew text to make it agree with the last clause, the subject changing there to the removal of evil from Judah.
thee: i.e. Judah (Nahum 1:13).