'Ambushers' in the Bible

Now Jeroboam had sent some men to ambush the Judahite army from behind. The main army was in front of the Judahite army; the ambushers were behind it.

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.