I hated that word “righteousness of God,” which, according to the use and custom of all the teachers, I had been taught to understand philosophically of the formal and active justice, as they called it, by which God is righteous and punishes sinners and the unrighteous. Though I lived as a monk without reproach, I felt I was a sinner before God with a most disturbed conscience. I could not believe that he was placated by my satisfaction. I did not love, indeed I hated the righteous God who punishes sinners. Secretly, if not blas- phemously, certainly murmuring greatly, I was angry with God. Yet I clung to the dear Paul and had a great yearning to know what he meant.
Finally by the mercy of God, as I meditated day and night, I paid attention to the context of the words, “In it the righteousness of God is revealed, as it is written, ‘He who through faith is righteous shall live.” Then I began to understand that the righteousness of God is that by which the righteous lives by a gift of God, namely by faith.
This, then, is the meaning: the righteousness of God is revealed by the gospel, viz. the passive righteousness with which the merciful God justifies us by faith, as it is written,“The righteous one lives by faith.” Here I felt that I was altogether born again and had entered paradise itself through open gates. There a totally other face of all Scripture showed itself to me. And whereas before “the righteousness of God” had filled me with hate, now it became to me inexpressibly sweet in greater love.
This passage of Paul became to me a gateway to heaven. Then I ran through Scripture, as I could from memory, and I found an analogy in other terms, too, such as the work of God, i.e., what God does in us, the power of God, with which he makes us strong, the wisdom of God by which he makes us wise,the strength of God, the salvation of God, the glory of God.
-Martin Luther, Preface to Latin Writings.