Martin Luther’s commentary on Galatians is indeed one of the finest expositions of this epistle of Paul as well as one of the finest discussions of justification through faith alone by grace alone in Christ alone. Luther’s introduction is also a gold mine. In it, he talks about active righteousness (our attempts at obedience) and passive righteousness (receiving righteousness as a gift). Here are a few excerpts:
…Human weakness and misery is so great that in the terrors of conscience and danger of death we see nothing but our works, our unworthiness, and the law. And when we are shown our sin, in time we remember the evil of our past life. Then the poor sinner groans with great anguish of spirit and thinks, “Alas, what a dreadful life I have lived! Would to God I might live longer; then I would amend my life.” Thus human reason cannot restrain itself from the sight of this active or working righteousness—that is, our own righteousness; nor can it look up to see the passive or Christian righteousness but relies altogether on the active righteousness—so deeply is this evil rooted in us.
On the other hand, Satan abuses our natural weakness and increases and aggravates these thoughts of ours. Then our poor conscience becomes more troubled, terrified, and confounded, for it is impossible for the human mind to conceive any comfort, or to look only to grace in the feeling and horror of sin, or to constantly reject all argument and reasoning about words. For this is far above human strength and ability, and indeed above the law of God as well. It is true that the law is the most excellent of all things in the world; yet it is not able to quiet a troubled conscience but makes our terrors worse and drives us to desperation—“so that through the commandment sin might become utterly sinful” (Romans 7:13).
Therefore, the afflicted and troubled conscience has no remedy against desperation and eternal death unless it takes hold of the forgiveness of sins by grace, freely offered in Christ Jesus—that is to say, this passive faith or Christian righteousness. If the conscience can take hold of this, then it may be at rest and boldly say, “I do not seek this active or working righteousness, although I know that I ought to have it, and also to fulfill it. But if I had it and did actually fulfill it, I still could not place my trust in it, nor should I dare to set it against God’s judgment. Thus I abandon all active righteousness, both of my own and of God’s law, and embrace only that passive righteousness that is the righteousness of grace, mercy, and forgiveness of sins. Briefly, I rest only on that righteousness that is the righteousness of Christ and of the Holy Spirit. Just as the earth does not generate rain and cannot of itself work to produce it, but receives it by the mere gift of God from above, so this heavenly righteousness is given us by God without our working for or deserving it.”
Martin Luther – preface to Galatians.