Isaiah 21:16

For thus hath the Lord said unto me
The prophet; which confirms what is before said, as well as assures the accomplishment of what follows: within a year, according to the years of an hireling;
that is, exactly and precisely, as soon as ever the year is come to an end; for the hireling, when his year is up, instantly demands dismissal from his service, or his wages, or both. The time is to be reckoned from the delivery of this prophecy; and so the calamity predicted was brought upon them by the Assyrians, perhaps under Sennacherib, when he invaded the cities of Judah, and might take Arabia in his way; less time is allowed than was the Moabites, who suffered by the same hand; see ( Isaiah 16:14 ) : and all the glory of Kedar shall fail;
these were another sort of Arabians, as the Targum calls them: they descended from Kedar, a son of Ishmael, ( Genesis 25:13 ) their "glory" were their multitude, their riches and substance, and which chiefly lay in their flocks; for the sake of which they moved from place to place for pasture, and dwelled in tents, which they carried with them, and pitched where it was most convenient for them; hence they were called Scenites; see ( Psalms 120:5 ) ( Song of Solomon 1:5 ) .