Repent therefore and be converted, that your sins may be blotted out, so that times of refreshing may come from the presence of the Lord, and that He may send Jesus Christ, who was preached to you before, whom heaven must receive until the times of restoration of all things, which God has spoken by the mouth of all His holy prophets since the world began. (Acts 3:19-21)
When I was a kid, I had this terrifying idea of Heaven and judgement. I had this picture in my head of God sitting on His throne, me standing there, small and scared, watching the movie of my life as He picked apart my every action. Mortifying! Then, when it was all over, all said and done, He would weigh all that sin against the grace and mercy of His son, and I'd escape Hell.
But "blotted out" tells us that's not what's going to happen. "Blotted out" says when I get to Heaven, what He's going to see is Christ in me, and then stack up how I've lived for Him. All that sin, all that filth, gone, as though it never happened.
See, God sees what we do. He knows when we sin, and that sin just piles up, slowly adding to the destruction of our immortal souls. That's life before repentance, and without Christ, that is the criteria on which we will be judged. But in Christ, we have the power to turn from that sin, and in the turning, leave it behind. And as Psalm 103 tells us, that transgression against His holiness is removed from us "as far as the East is from the West." It's no longer a part of us. It no longer holds us back, and is no longer even recognized by God.