Albert Barnes Commentary Nahum 3:15

"There shall the fire devour thee; the sword shall cut thee off; it shall devour thee like the canker-worm: make thyself many as the canker-worm; make thyself many as the locust." — Nahum 3:15 (ASV)

There—where you fenced yourself, and made such extensive and laborious preparation,

The fire shall devour you.—All is toil within. The fire of God’s wrath falls and consumes at once. Mankind still, with mire and clay, build themselves Babels. They go into clay, and become themselves earthly like the mire they steep themselves in. They make themselves strong, as though they thought that their houses shall continue forever (Psalms 49:11), and say, So, take your ease, eat, drink, and be merry (Luke 12:19–20).

God’s wrath descends. "You fool, this night your soul shall be required of you. It shall eat you up like the cankerworm." What in you is strongest shall be devoured with as much ease as the locust devours the tender grass. The judgments of God not only overwhelm as a whole, but find out each tender part, as the locust devours each single blade.

Make yourself as numerous as the cankerworm—As though you would equal yourself in oppressive numbers to those instruments of God's vengeance, gathering armies from all quarters to help you; yes, though you make your whole self one oppressive multitude, yet it shall not avail you. No, He says, you have attempted to do it.