Some translations prefer to set apart extended quotations, prayers and songs. The ULB and many other English translations set the lines of the entire book (except for verse 1 of this chapter) farther to the right on the page than regular text because they are poetic prophecy. (See: [[rc://en/tw/dict/bible/kt/prophet]])
This prophecy should be read in reference to the book of Jonah. That book described how the people of Niniveh, Assyria's capital city, repented when Jonah warned them that Yahweh was angry at them. The book of Nahum, written a little over one hundred years later than when Jonah was set, indicates that the Ninevites would be punished by God, but only after he had used them for his own purposes. These actions of Yahweh, although described as vengeance or anger, do not have the same sinful quality as they usually do with humans. (See: [[rc://en/tw/dict/bible/kt/evil]], [[rc://en/tw/dict/bible/other/avenge]] and [[rc://en/tw/dict/bible/kt/sin]])
At that time, Assyria controlled almost the entire Near East. Nahum prophesied that the Assyrians would be so completely destroyed as a nation that they would no longer even be a people group. This prophecy came true very suddenly.