they saw one another: That is, "they fought against each other." To face an enemy, or to face one another, is still a common expression. The reason of this war was evidently the injury the army of Joash had done to the unoffending inhabitants of Judah. The ravages committed by them were totally unprovoked, base, and cowardly: they fell upon women, old men, and children, and butchered them in cold blood, when all the effective men were gone with their king against the Edomites. The quarrel of Amaziah were certainly just, yet he was put to the rout. He fell, and Judah with him, as Joash had said; and the reason was, because "it came of God, that he might deliver them into the hands of their enemies, because they sought after the gods of Edom." This was the reason why the Israelites triumphed. 2 Chronicles 25:17
Bethshemesh: Joshua 21:16; 1 Samuel 6:9, 1 Samuel 6:19-20