21 When he had taken counsel with the people, he appointed those who should sing to Yahweh, and give praise in holy array, as they went out before the army, and say, Give thanks to Yahweh; for his loving kindness endures forever. 22 When they began to sing and to praise, Yahweh set ambushers against the children of Ammon, Moab, and Mount Seir, who had come against Judah; and they were struck. 23 For the children of Ammon and Moab stood up against the inhabitants of Mount Seir, utterly to kill and destroy them: and when they had made an end of the inhabitants of Seir, everyone helped to destroy another. 24 When Judah came to the place overlooking the wilderness, they looked at the multitude; and behold, they were dead bodies fallen to the earth, and there were none who escaped.
Matthew Henry's Commentary on 2 Chronicles 20:21-24
Commentary on 2 Chronicles 20:20-30
(Read 2 Chronicles 20:20-30)
Jehoshaphat exhorted his troops to firm faith in God. Faith inspires a man with true courage; nor will any thing help more to the establishing of the heart in shaking times, than a firm belief of the power, and mercy, and promise of God. In all our trust in the Lord, and our praises of him, let us especially look at his everlasting mercy to sinners through Jesus Christ. Never was an army so destroyed as that of the enemy. Thus God often makes wicked people destroy one another. And never was a victory celebrated with more solemn thanksgivings.