Carl Friedrich Keil and Franz Delitzsch Old Testament Commentary

The Lord would give peace in the land, and cause the beasts of prey which endanger life to vanish out of the land, and suffer no war to come over it, but would put to flight before the Israelites the enemies who attacked them, and cause them to fall into their sword. שׁכב, to lie without being frightened up by any one, is a figure used to denote the quiet and peaceable enjoyment of life, and taken from the resting of a flock in good pasture-ground (Isa 14:30) exposed to no attacks from either wild beasts or men. מחריד is generally applied to the frightening of men by a hostile attack (Mic 4:4; Jer 30:10; Eze 39:26; Job 11:19); but it is also applied to the frightening of flocks and animals (Isa 17:2; Deu 28:26; Jer 7:33, etc.). רעה חיּה: an evil animal, for a beast of prey, as in Gen 37:20. "Sword," as the principal weapon applied, is used for war. The pursuing of the enemy relates to neighbouring tribes, who would make war upon the Israelites. לחרב נפל does not mean to be felled by the sword (Knobel), but to fall into the sword. The words, "five of you shall put a hundred to flight, and a hundred ten thousand," are a proverbial expression for the most victorious superiority of Israel over their enemies. It is repeated in the opposite sense and in an intensified form in Deu 32:30 and Isa 30:17.