2 Kings 14:1-14

“In the second year of King Joash son of Ahaziah of Israel, King Amaziah son of Joash of Judah began to reign,” who avenged the death of his father, but with moderation, so that he spared the life of the relatives of the conspirators according to the prescriptions of the Law and was careful that the punishment might not be too excessive for the authors of the crime. Therefore Amaziah was pious, as long as he had before his eyes his father’s unhappy end, whose cause he could not ignore: offense against the true religion [of God]. However, when his reign began to be very prosperous, [Amaziah] rejected his fear of God which he had conceived after witnessing his father’s punishment, and embraced foreign cults. In the second book of the Annals, the Scripture relating his victory against the Edomites confirms that this was the reason of his apostasy: “But Amaziah took courage, and led out his people, and went to the Valley of Salt and smote ten thousand men of Seir. The men of Judah captured another ten thousand alive and took them to the top of a rock, and all were enchained.” And the text adds, “After Amaziah came from the slaughter of the Edomites, he brought the gods of the men of Seir, and set them up as his gods and worshiped them, making offerings to them.”

The Almighty, who cannot possibly will anything unjust, is able to set in motion even the inclinations of their will in people's hearts in order to accomplish through these people whatever he wishes to achieve through their agency. What meaning can these words have that the man of God addressed to King Amaziah: "Do not allow the army of Israel to go out with you, for the Lord is not with Israel and all the children of Ephraim. And if you think to prevail over them, God will put you to flight before your enemies; for it belongs to God both to help and to put to flight"?How does the power of God help some in war by giving them confidence and turns others to flight by instilling them with fear, except for this reason, that he who has made all things as he willed in heaven and on earth, also works in the human hearts? We also read of what Joash, king of Israel, said when he dispatched a messenger to King Amaziah, who had a mind to go to war with him. Having mentioned certain things, he went on to say, "Sit at home. Why do you provoke evil that you should fall and Judah with you?" The Scripture then went on to add, "And Amaziah would not listen to him because it was the Lord's will that he should be delivered into the hands of enemies because he sought after the gods of Edom."
There you see how God, wishing to punish the sin of idolatry, influenced the heart of this man with whom he was justly angry, that he would not heed salutary advice but, in his contempt for it, would engage in battle, there to perish together with his army.

"He struck down ten thousand Edomites in the Valley of Salt, etc." [2 Kings 14:7] It is said of Amaziah, the king of Judah: He struck down ten thousand Edomites in the Valley of Salt, and took Sela in war, and called its name Joktheel; the Valley of Salt was where they made salt, either from a spring of brine, as in many places, or by cutting, drying, and burning, or by boiling salty well waters until they solidified into salt, or by any other method by which salt is usually made. In that place, Joab is also recorded to have struck down twelve thousand Edomites. It must also not be overlooked that the old edition, for the Valley of Salt, placed Gemelach, as if it were the name of a region. Petra, however, is a noble city of Arabia, in the same land of Edom, which in the Book of Numbers is called Rekem, and by the Syrians today is still called thus (Num. 31). Joktheel, which Amaziah as victor gave it as a name, is interpreted as the assembly of God, or the help of God, acting faithfully so that it would be recorded for perpetual memory, because he took it either with the assembly of the people of God or with God's help.

The thorn bush [mentioned here] is a tiny plant and herb and is not the blackberry bush, [whose fruits] we eat. “Since, if ever,” he says, “the thorn bush were sent to a cedar, saying, ‘Give your daughter to my son for a wife,’ it would be an insult and an act of derision, since the thorn bush is much smaller than the cedar, so you, Amaziah, do not differ at all from the thorn bush, if compared with my power.” By the cedar and the wild beast Jehoash signifies himself.

Let us see one another: This was a challenge to fight.