In this excerpt from Luther and the Reformation, R.C. Sproul describes the moment of awakening Martin Luther had as he read Romans 1:17, “For in it the righteousness of God is revealed from faith for faith, as it is written, ‘The righteous shall live by faith.’”
He says, “Here in it,” in the gospel, “the righteousness of God is revealed from faith to faith, as it is written, ‘the just shall live by faith.’” A verse taken from the book of Habakkuk in the Old Testament that is cited three times in the New Testament. As Luther would stop short and say, “What does this mean, that there’s this righteousness that is by faith, and from faith to faith? What does it mean that the righteous shall live by faith?” Which again as I said was the thematic verse for the whole exposition of the gospel that Paul sets forth here in the book of Romans. And so, the lights came on for Luther. And he began to understand that what Paul was speaking of here was a righteousness that God in His grace was making available to those who would receive it passively, not those who would achieve it actively, but that would receive it by faith, and by which a person could be reconciled to a holy and righteous God.
Now there was a linguistic trick that was going on here too. And it was this, that the Latin word for justification that was used at this time in church history was—and it’s the word from which we get the English word justification—the Latin word justificare. And it came from the Roman judicial system. And the term justificare is made up of the word justus, which is justice or righteousness, and the verb, the infinitive facare, which means to make. And so, the Latin fathers understood the doctrine of justification is what happens when God, through the sacraments of the church and elsewhere, make unrighteous people righteous.
But Luther was looking now at the Greek word that was in the New Testament, not the Latin word. The word dikaios, dikaiosune, which didn’t mean to make righteous, but rather to regard as righteous, to count as righteous, to declare as righteous. And this was the moment of awakening for Luther. He said, “You mean, here Paul is not talking about the righteousness by which God Himself is righteous, but a righteousness that God gives freely by His grace to people who don’t have righteousness of their own.”
And so Luther said, “Woa, you mean the righteousness by which I will be saved, is not mine?” It’s what he called a justitia alienum, an alien righteousness; a righteousness that belongs properly to somebody else. It’s a righteousness that is extra nos, outside of us. Namely, the righteousness of Christ. And Luther said, “When I discovered that, I was born again of the Holy Ghost. And the doors of paradise swung open, and I walked through.”