(20) In his days Edom revolted.--The connection of ideas is this: Although Jehovah was not willing to extirpate Judah, yet He suffered it to be seriously weakened by the defections recorded in 2Kings 8:20-22.

Made a king over themselves.--Josephus says they slew the vassal king appointed over them by Jehoshaphat (1Kings 22:48). Edom appears to have been subject to the hegemony of Judah from the time of the disruption under Rehoboam.

Verse 20. - In his days Edom revolted from under the hand of Judah. Edom had been conquered by Joab in the time of David, and had been treated with great severity, all the males, or at any rate all those of full age, having been put to death (1 Kings 11:15, 16). On the death of David, Edom seems to have revolted under a prince named Hadad, and to have re-established its independence. It had been again sub-jeered by the time of Jehoshaphat, who appointed a governor over it (1 Kings 22:47), and treated it as a portion of his own territories (2 Kings 3:8). Now the yoke was finally thrown off, as had been prophesied (Genesis 27:40). Edom became once more a separate kingdom, and was especially hostile to Judah. In the reign of Ahaz the Edomites "smote Judah" and carried away many captives (2 Chronicles 28:17). When the Chaldaeans attacked and besieged Jerusalem, they cried, "Down with it, down with it, even to the ground!" (Psalm 137:7). They looked on with joy at the capture of the holy city (Obadiah 1:12), and "stood in the crossway, to cut off such as escaped" (Obadiah 1:14). After the return from the Captivity, they were still Judah's enemies, and am especially denounced as such by the Prophet Malachi (Malachi 1:3-5). In the Maccabee wars, we find them always on the Syrian side (1 Mac. 4:29, 61 1 Mac. 5:3 1 Mac. 6:31; 2 Macc. 10:15, etc.), doing their best to rivet the hateful yoke of the heathen on their suffering brethren. As Idumaeans, the Herodian family must have been specially hateful to the Jews. And made a king over themselves. The king mentioned in 2 Kings 3:9, 26 was probably a mere vassal king under Jehoshaphat.

8:16-24 A general idea is given of Jehoram's badness. His father, no doubt, had him taught the true knowledge of the Lord, but did ill to marry him to the daughter of Ahab; no good could come of union with an idolatrous family.In his days Edom revolted from under the hand of Judah,.... Who had been tributary to Judah ever since the times of David, for the space of one hundred and fifty years:

and made a king over themselves; for though they are said to have kings, those were only deputy kings, as in 1 Kings 22:47 and now the prediction of Isaac began to be accomplished, Genesis 27:40.