"But you are pure and cannot stand the sight of evil. Will you wink at their treachery? Should you be silent while the wicked swallow up people more righteous than they?"
- Habakkuk 1:13
Why must God judge people? Answer: because He is righteous and holy. We see this repeated again and again in Scripture. In Revelation 4:8, we read about angelic beings coming before the Lord, not resting day or night, and repeating over and over again, "Holy, holy, holy is the Lord God, the Almighty-the one who always was, who is, and who is still to come."
Notice they don't say, "Faithful, faithful, faithful" or "Eternal, eternal, eternal," though He is all of those things. Instead, they emphasize God's holiness. And because God is holy, He cannot look at sin (see Habakkuk 1:13).
And although God's judgment is a horrible thing, there are still some positive aspects to it.
It frightens us. And guess what? It is supposed to. When we see what happens to others who disregard what God's Word says, it should cause us to think twice about what we are about to do.
It sobers us. It forces us to reassess the way we have been living our lives and hopefully change our priorities. As C. S. Lewis pointed out, pain is God's megaphone to rouse a deaf world.
It humbles us. God's judgment strips away our self-righteousness and reminds us about how sinful we are. It reminds us that we are not really in control of our lives and how we really need God.
It reassures us. The fact that there will be a final judgment reassures us there is justice in the universe. We all know of wicked people in the world who deserve judgment. The Bible says there is a final court of arbitration, and God keeps meticulous records of everything that happens in this world. The wicked will be held accountable for what they have done. And it is reassuring to know there ultimately will be justice.