2 Chronicles 20:22

And when they began to sing and to praise, the LORD set ambushments against the children of Ammon, Moab, and mount Seir, which were come against Judah; and they were smitten.

Ver. 22. And when they began to sing and to praise.] So at the siege of Mountabon, the people of God using daily humiliation as their service would permit, did sing a psalm after and immediately before their sallying forth. With which practice the enemy coming acquainted, ever upon the singing of the psalm, after which they expected a sally, they would so quake and tremble, crying, "They come, they come," as though the wrath of God and the rage of all the creatures had been breaking out upon them.

The Lord set ambushments.] Furor hostibus a Deo immissus ut in se invicem efferati saevire non desisterent, donec mutuis caedibus sese prostravissent. The wrath of God wrought their ruin, as by an ambush, unexpectedly and irresistibly. Some understand this ambush of the holy angels, sent suddenly in upon them to slay them; whereupon they mistaking the matter, and supposing it had been their own companions, flew upon them, and so sheathed their swords in one another's bowels.