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 this chapter.
This chapter prophesied the destruction of Babylon. At the time that the prophesy was written, Assyria was still in power and Babylon had not yet become a world power. The Chaldeans were not yet a powerful nation either. The people of Judah would become servants or slaves of Babylon and be forced to work very hard. (See: [[rc://en/tw/dict/bible/kt/prophet]])