There was no king in Edom; a deputy was king.
Here is, I. A short account of the reign of Jehoshaphat king of Judah, of which we shall have a much fuller narrative in the book of Chronicles, and of the greatness and goodness of that prince, neither of which was lessened or sullied by any thing but his intimacy with the house of Ahab, which, upon several accounts, was a diminution to him.
Commenting on 1 Kings 22:41-53
[There was] then no king in Edom: a deputy [was] king. (b) In the time of this king, Idumea was subject to Judah, and was governed by whom they of Judah appointed.
There was no king in Edom - It is plain that the compiler of this book lived after the days of Jehoshaphat, in whose time the Edomites revolted; see Kg2 8:22. David had conquered the Edomites, and they continued to be governed by deputies, appointed by the kings of Judah, till they recovered their liberty, as above.