God is full of wrath and will end His enemies for good.
Israel can take heart because the brutal and idolatrous Assyrian won't pass through Israel anymore.
Nineveh's downfall is poetically described - the spears, torches and chariots in the streets, the women carried off moaning, the gold plundered.
More description. Stumbling over dead bodies in the street.
God is against Nineveh because of her prostitution (3:4-5). She inflicted evil on everyone (3:19).
She's no different than other cities that have fallen. Her wealth will take wings like the grasshopper and fly away.
You'll end scattered and mortally wounded with no healing in sight.
How this is about Jesus
He also promises judgment and a painful end for His enemies (1 Thess. 5:3; 2 Thess. 1:5-8; Rev. 19:15).
It can be hard for Western Christians, facing little hostility from enemies of Christ until very recently, to understand the solace believers can draw from texts such as these. This comfort doesn't come from a desire to "get them back" personally, but to see Christ's name and sovereignty vindicated after His people are trampled under and killed.