For godly grief produces a repentance that leads to salvation without regret, whereas worldly grief produces death.--2 Corinthians 7:10 (ESV)
In this verse, Paul outlines the path to happiness. The interesting thing about this path is that it begins with sadness. You have to walk over the rough patch of godly grief before you can walk on the streets of gold. Essentially, Paul maps out the path to happiness as (1) Godly grief for sin leads to (2) repentance from sin which produces (3) salvation without regret (which I'm going to refer to as simply happiness).
Grief which stems from our wounded pride does not please God and is ineffectual in producing repentance. This is, I believe, the "worldly grief" which produces death. John Owen, in his treatise The Mortification of Sin, writes of this worldly grief: "Now it is certain that that which I speak of proceeds from self-love. Thou settest thyself with all diligence and earnestness to mortify such a lust or sin: what is the reason of it? It disquiets thee; it hat thaken away thy peace; it fills thy heart with sorrow and trouble and fear; thou hast no rest because of it. . . . Would thy conscience be quiet under it, thou wouldest let it alone. Did it not disquiet thee, it should not be disquieted by thee."
The word "godly" means either "devout and pious" or "coming from God." If we apply both of these meanings to this verse, we see that the grief which truly leads to happiness is centered on God. It is, in John Owen's words: "Hatred of sin as sin, not only as galling or disquieting." Godly grief is being saddened by our grieving of the Holy Spirit. Godly grief is mourning our part in Christ's crucifixion. Godly grief is thinking: "This sin is like walking up to Christ dying for me on the cross--and spitting on His face." Under this grief, a soul cannot tolerate the smallest sin and genuinely repents.
The path to happiness begins with a look at Calvary. Until the Holy Spirit opens up the majesty of the Gospel to our souls, our grief will be worldly. With His help, however, we can grieve for our sin in a godly way and genuinely repent. Let us pray for the Holy Spirit to give us a godly grief for our sin--that we may have salvation without regret.