A skeptic once asked a minister if he really believed the Bible. Yes, he was told. "Is there anything you can't explain?" was the next question. Yes again—the minister even showed him the question marks in the margins of his Bible. Surprised, the skeptic asked, "What do you do with all the things you can't explain?" "Very simple," the minister replied. "I do the same thing I'm doing with this fish I'm eating. I eat the meat and push all the bones to the side of the plate, and then let any fool that wants to choke over them."
Our finite minds cannot fully comprehend the ways of our infinite God. Even so, He communicates and reveals Himself in ways that we can understand. So God answered Habakkuk's second question, at least as far as the prophet could understand the answer. As we see today and tomorrow, He assured him that the evil instrument of Judah's punishment would in turn be punished and that the scales of justice would balance in the end. Babylon would fall.
God certainly agreed with Habakkuk's moral estimate of the Babylonians (vv. 4-5). They were proud and lusted for power. "He is as greedy as the grave and like death is never satisfied." This didn't square with the principle that the righteous live by faith (or faithfulness), a truth quoted in the New Testament in several places (such as Rom. 1:17).
That's why God pronounced five woes on the Babylonians. The first (vv. 6-8) said that the plunderers would become the plundered—unjust gains must be paid for. The second (vv. 9-11) indicated that the plotters of ruin would themselves be ruined and that no one is beyond the reach of God's sovereign hand. These "woes" are statements of judgment as well as "taunt songs"—a literary form in which losers are mocked. The wicked will receive justice from the hand of God in His due time. The basic idea is, "They finally got their just desserts, they had it coming."