From Martin Luther’s introduction to his Commentary on the Epistle to the Galatians:
Then do we do nothing and work nothing in order to obtain this righteousness? I reply: Nothing at All. For this righteousness means to do nothing, to hear nothing, and to know nothing about the Law or about works but to know and believe only this: that Christ has gone to the Father and is now invisible; that He sits in heaven at the right hand of the Father, not as a Judge but as one who has been made for us wisdom, righteousness, sanctification, and redemption from God; in short, that He is our High Priest, interceding for us and reigning over us and in us through grace. Here one notices no sin and feels no terror or remorse of conscience. Sin cannot happen in this Christian righteousness; for where there is no Law, there cannot be any transgression. If, therefore, sin does not have a place here, there is no conscience, no terror, no sadness.
It is difficult to contribute any more words to such a potent unfolding of the gospel.
It might be interesting to note that Luther’s life was punctuated by periods of deep depression. Whether his depression was chemical or circumstantial or theological, I am grateful to have found a preacher of the gospel whose mind is as dark and whose thoughts are as desperate as mine often are. When Luther talks about joy, you can believe him because he is well-acquainted with those moments entirely devoid of joy.
No other spiritual devotion or religious exercise will give you the peace that comes when you simply remind yourself “It is finished.” There is no more to do. You are loved. You are free.