For again. — And moreover.
Smitten Judah. — Smitten in Judah, i.e., inflicted a defeat upon her. After their reduction by Uzziah, the Edomites had probably remained subject to Judah, until Rezin of Syria expelled the Jews from Elath (2 Kings 16:6), and restored it to them. After that event, the disasters of Ahaz seem to have encouraged them to make a raid upon his territory.