F it weren't for Nahum 2:8 & 13, we might have a tough time figuring out what chapter 2 is all about. But, based upon those verses we can tell that Nahum is speaking about the demise of Nineveh. He uses what seems to me to be an intensely poetic style in this chapter to describe the fall of Nineveh, but the result is plain enough. The same thing that Assyria had done to Israel (Nahum 2:2) was going to be done to Nineveh. And, just like Assyria won as a result of a providential purpose, so also the fall of Nineveh would be the result of God's intervention. The invading Babylonians (Nahum 2:4) and the flood of the Tigris river (Nahum 2:6) were certainly not incidental. Nineveh had made God their enemy. They had owned the truth previously (during the days of Jonah), but by the time Nahum came around, they had forsaken it altogether. Just like Isaiah wrote to his audience, "Truth is fallen in the street, and equity cannot enter" (Isaiah 59:14). Nineveh was doomed because Nineveh was wicked.
The only hope for Nineveh lay in their humble acceptance of the absolute authority and exclusivity of the one true God of Abraham, Isaac and Jacob. At one point, He had been the God of Nineveh too (see Jonah 3:10). But their rejection of Him and of His truth was complete. Remember, "Blessed is the nation whose God is the LORD..." (Psalm 33:12, 18 & 19), and, "Righteousness exalts a nation: but sin is a reproach to any people" (Proverbs 14:34). That should make us consider the condition of our own nation.