Nahum was on a roll from the very first verse of his prophetic message. Actually, his first verse is the second verse of the first chapter...the first verse of the first chapter merely states the authorship. Verse 2 hits it hard - "The Lord is a jealous and avenging God; the Lord takes vengeance and is filled with wrath."
Nahum started out invoking the great and avenging God of the universe in prophesying vengeance upon Judah's enemies. He proceeds to blast Nineveh with prose. Nahum's profound understanding of God is framed early-on in this prophesy in one single verse, ranging from God being "slow to anger and great in power..." to "(He) will not leave the guilty unpunished."
Wow, I wish I could reach back into time and eternity and pull out a recording of Nahum preaching this! I love to hear good preaching. Now, by 'good' preaching I mean someone who can MOVE me. Nahum was that kind of preacher. He was filled with passion! He was a wordsmith - a master communicator, a man who knew how to make words flow with the heat and fluidity of molten lava, sizzling as it hit the sea.
Have you ever been so full of anger that it would bring passion and intensity to the surface in a heartbeat of personal injustice or inequity? That's where Nahum was emotionally and spiritually - and God chose to use that burning, passionate intensity to drive home quite a mixed message.
Did you notice the other part of the message...that made it 'mixed'? Look again at how that verse starts: "The Lord is slow to anger and great in power; the Lord will not leave the guilty unpunished." Nahum 1:3
If only the people of Nahum's day would have paid attention to the first message in these verses - they could have avoided the second. And, if the people of Judah would have learned from the calamity of the Ninevites they could have avoided their own calamity a few years later at the hands of those same Babylonians.
Isn't it sad that even today humanity doesn't seem to learn from the message of Grace? Isn't it sad that we still aren't learning from the lessons of others, past and present?
Even as great and passionate a preacher as Nahum wasn't able to 'move' the people to understand that God is, indeed, slow to anger and great in power; He is good and a refuge in times of trouble, caring for those who trust in Him.
But God is...and He is a rewarder of those who diligently seek Him. Those who don't find Him in His goodness, will eventually find Him in His judgment. "God is not mocked, whatsoever a man soweth that shall he also reap."