Some translations set each line of poetry farther to the right than the rest of the text to make it easier to read. The ULB does this with the poetry in 50:1-5, 6-46.
Babylon will be conquered and the Jews will return to their homeland. At this time, Babylon controlled almost the entire Near East. The fulfillment of this prophecy would have been unthinkable. (See: [[rc://en/tw/dict/bible/kt/fulfill]] and [[rc://en/tw/dict/bible/kt/prophet]])
The author sometimes uses the term "Israel" to refer to the people of the old northern kingdom of Israel, and at other times to the nation of Israel as a whole. He switches between these uses several times without warning the reader. (See: [[rc://en/ta/man/jit/figs-explicit]])