Psalm 139:23-24, Luke 18:9-14, James 1:5, Romans 12:2, Proverbs 3:5-6
The problem is, many of the people in need of saving are in churches, and at least part of what they need saving from is the idea that God sees the world the same way they do.
Sin is looking to something else besides God for your salvation. It is putting yourself in the place of God, becoming your own savior and lord, as it were.