Some translations set poetry farther to the right than the rest of the text to show that it is poetry. The ULB does this with the poetry in 16:19-21. This poem also continues in chapter 17, and these should be seen as one section.
The punishment that is prophesied in this chapter will happen quickly. The author gives many illustrations which describe how quickly this punishment will come. (See: [[rc://en/tw/dict/bible/kt/prophet]])
God will bring his people back from captivity. Even though the punishment of Judah will be great, Yahweh promised a future restoration. (See: [[rc://en/tw/dict/bible/kt/promise]] and [[rc://en/tw/dict/bible/kt/restore]])