“the mouth of the sword.” Used to show great destruction, as if the sword was eating its victims (see commentary on Josh. 6:21).
“from the Arnon to the Jabbok.” From the Arnon Valley on the south (which was the northern border of Moab; Num. 21:13) to the Jabbok River valley on the north, which was the southern border of the territory of Og of Bashan.