From a sermon by John Piper (found on his site). Rom 3:21-22
This is the best news for those of us who feel the guilt and shame of our sins. We who know our guilt before the Lord God feel the heavy burden of God's Judgment on us. But we have this Promise in Christ: that there is a righteousness available through faith in Jesus Christ. No matter how evil my sin has been, no matter how many years I have engaged in wickedness, no matter how many good works I have done, they all have no meaning to the Righteousness of God. A real and true righteousness is made available by faith in Christ and by faith alone. This is good news. I neither have to compensate for this righteousness or work to earn (merit) it. It is imparted by faith in Christ. Simple, plain and yet deep and remarkably astounding.