Albert Barnes Commentary Nahum 1:12

"Thus saith Jehovah: Though they be in full strength, and likewise many, even so shall they be cut down, and he shall pass away. Though I have afflicted thee, I will afflict thee no more." — Nahum 1:12 (ASV)

Though they are quiet and also many, yet in this way they will be cut down – Literally, this means, If they are entire—that is, sound, unharmed, unimpaired in their numbers, unbroken in their strength, undiminished, and perfect in all that pertains to war. It also means, and thus many, even thus will they be mown down (or shorn), and he passes away. With might outwardly unscathed, without hand (Daniel 2:34), and "thus many"—that is, many, accordingly, as being unweakened. As many as they will be, so will they be mown down, and he, their head and king, will pass away and perish . Their numbers will be, as their condition before, perfect; their destruction, like their numbers, complete.

It is wonderful how much God says in few words, and how it is here foretold that, with no previous loss, a mighty host—secure and at ease in consequence of their prosperity—all are at one blow mown down like the dry grass before the scythe, are cut off and perish. And one, their king, passes away, first by flight, and then by destruction. As they had shorn the glory of others (Isaiah 7:20), so they themselves should be shorn and cut down.

Though I have afflicted you, I will afflict you no more – Unless by new guilt you compel Me. God always relieves us from trouble, as it were, with the words, sin no more, lest a worse thing come unto thee (John 5:14). In the end, afflictions will be turned into joy, and God shall wipe away all tears from their eyes; and there shall be no more death, nor sorrow, nor crying, neither shall there be anymore paid (Revelation 21:4).