So then, we have nothing to do to obtain this righteousness? No, nothing at all! For this righteousness comes by doing nothing, hearing nothing, knowing nothing, but rather in knowing and believing this only — that Christ has gone to the right hand of the Father, not to become our judge, but to become for us our wisdom, our righteousness, our holiness, our salvation!
Now God sees no sin in us, for in this heavenly righteousness sin has no place. So now we may certainly think, "Although I still sin, I don't despair, because Christ lives, who is both my righteousness and my eternal life." In that righteousness I have no sin, no fear, no guilty conscience, no fear of death. I am indeed another righteousness above this life, which is in Christ, the Son of God, who knows no sin or death, but is eternal righteousness and eternal life.
"Martin Luther's preface to Galatians (paraphrase by Tim Keller)," Paul's Letter to the Galatians: Participant's Guide. Tim Keller, Redeemer Presbyterian Church. 2003.d