What is sin?
One of my teachers in high school described sin as anything that misses the mark (God's holiness). It is used in archery to describe the same thing, missing the bulls-eye. This means that anything we do that does not hit God's bulls-eye dead center is considered sin. I don't know about you, but I'm not the most accurate shooter out there. Sometimes, I'm not even shooting at the target! And as Paul reminds us Romans 6:23, "the wages of sin is death."
As I have grown in my faith, my sins have come more apparent to me and I have seen the progression a sin takes in my life. It starts by creeping its head out and letting me know its there. Then it begins to become bolder and present itself in the most appealing way it can. Like a siren on the sea it lures me into its grasp. At this point I am at a crossroads: give in to sin or stand strong in my faith. When I choose the former, there is an ephemeral pleasure that fades as quickly as it came. Suddenly, I come to my senses, realize what I have done, and guilt washes over me. It is miserable feeling that spiritual separation. But when I choose the latter, the temptation leaves and I am left with a peace that only God can give.
Our best defense against any sin is to flee and head straight to the cross. It is there that we find our redemption and a love that surpasses all understanding. Its at this place that we see the other part of Romans 6:23, "the gift of God is eternal life in Jesus Christ our Lord." Even though we may not always hit the bulls-eye, God's gift is still there for us.
I think Matt Chandler sums it up very nicely in his book "The Explicit Gospel." "My sin in the past: forgiven. My current struggles: covered. My future failures: paid in full all by the marvelous, infinite, matchless grace found in the atoning work of the cross of Jesus Christ."