Rick Gamache of Sovereign Grace Church, Minneapolis recently preached this hard-hitting sermon, challenging Christians to deal with root of our sin. His title, A Functional Doctrine of Sin, summarizes the focus of his purpose, to give us a practically functioning mindset and approach to dealing honestly and seriously with our sin.
One of his quotes (perhaps from Ralph Venning) says we must understand the evilness of sin because the evil of sin is what cost the Savior his blood (my poor paraphrase from memory).
Excellent sermon on sin, in addition to the fact that there are few sermons on sin.