It's often said that one of the benefits of Christ's death for sinners is that He gives us all a clean slate, meaning that He has washed away our sins, and they can no longer condemn us.
That is good news, as far as it goes. But the gospel brings us good far greater than a clean slate. Because of Jesus God gives us a slate with a lot of writing on it; things like this:
I always do the things that are pleasing to God.
I am so focused on doing the will of God that it is my daily food.
I don't seek my own will, but God's will instead.
I have kept all of God's commandments.
I live in such a way that my life brings holiness to others.
I love others and lay down my life for them.
I live in such a way that people around me know that I love my heavenly Father more than anything else.
All this, though it seems manifestly untrue in your life, is indeed true of you and written on your slate because it is true of Jesus, and by faith you have been united to Him. His perfect obedience and righteousness is yours, just as your sin and judgment has become His, and was punished once for all on the cross.
So, Christian, your slate is not clean. It has a lot of writing on it, and that is really good news. If all I got from Jesus was a clean slate, I'd surely mess that slate up again quite quickly. By grace, my slate is filled with Christ's perfect obedience.