We are making a confession of the realities of sin and the holy God. When we come to the atonement, then we understand that our great problem is our sin, our inability to remove our sin, and our deserving of punishment before God. Unless this reality, this burden of sin is brought personally to your soul, there is no point in going any further in the explanation of the doctrine of the atonement. For the atonement of Jesus Christ does not come hanging on a sky-hook, dropped out of the blue. But the atonement stands in the concrete reality of our sin, and our sin in the presence of God.
Sin is a horrible thing.
Sin deserves everlasting punishment because of who God is. The God of the Bible is essentially holy and good, pure from all iniquity. So we might read in Hebrews 12, our God is a consuming fire. He is a God of inflexible justice. He always does the right.