To answer Ren and Daniel about falling into sin and leaving them unconfessed (ie. caught red-handed when the Rapture comes -- I always picture myself on the toilet or in the shower, m'self LOL) - YES, you will be Raptured.
The thought that we must repent of our sins over and over in order to be saved means that you would need to CONTINUALLY be saved again and again by the blood of Jesus for each sin, that it would be INSUFFICIENT to cover all your sins.
No, Christ died ONCE for ALL.
The idea behind repentence once you're saved is to realize you've sinned, to grow in your walk with God, and to acknowledge that what you did broke His heart. Your very first repentence to become a believer COVERED ALL the sins you've ever done, and all that you WILL EVER do.
If Christ's atonement doesn't cover future sin, then we are ALL LOST. He died 2000 years ago for our future sin. Therefore, if we're a believer today yet sin tomorrow, that sin has already been bought and paid for.
The repentence of a believer is for you to confess to God you got dirty, but that you're going to get right back on your feet and live like Christ. The narrow path is FULL of brambles, roots, potholes, rocks, quicksand, felled trees, and all kinds of things that make us stumble or take a step back. BUT, these hardships are what A.) keep us humble, B.) teach us, C.) guide us in the way we should go.
If we stumble three times at the same pothole, maybe the next time we can avoid it. And perhaps we can warn others to sidestep it too! If we come across a felled tree, God wants to see how we choose to climb over it. These things bring us to a closer, more intimate relationship with God. Not that God WANTS us to sin, but that in the act of repentence, our heart is open, we're humble before Him, and we want more than ever to please Him.
And that is when Christ says to you, "Go, and sin no more."
He has already forgiven you, but He WANTS you to continue to turn back to Him and learn from your mistakes, not to purposefully seek out the quicksand and the brambles. Remember, Christ knows your heart, and He knows when you're penitent and when you're just giving lip service in repentence.
So if you've fallen into that pothole when Christ returns, He'll Rapture you. You're already clean. And your sin will be thrown into the fire and burnt up once you stand before His Bema Seat. Otherwise His work at the cross means nothing.
Whom have I in heaven but You? And there is nothing on earth that I desire besides You. My flesh and my heart may fail, but God is the strength of my heart and my portion forever. ~~Psalm 73:25-26 (ESV)