Martin Luther, John Calvin, Richard Hooker, Herman Bavinck, Karl Barth—they wrestled with the concerns of the Church catholic and provided answers to the questions Catholicism had taught me to pose. Richard Hooker interpreted the Church’s traditions; Calvin followed Luther’s Augustinianism, proclaimed the visible Church the mother of the faithful, and claimed for the Reformation the Church’s exegetical tradition; Barth convinced me that God’s Word could speak, certainly and surely, from beyond all created realities, to me.

Catholicism had taught me to think like a Protestant, because, as it turned out, the Reformers had thought like catholics. Like their pope-aligned opponents, they had asked questions about justification, the authority of tradition, the mode of Christ’s self-gift in the Eucharist, the nature of apostolic succession, and the Church’s wielding of the keys. Like their opponents, Protestants had appealed to Scripture and tradition. In time, I came to find their answers not only plausible, but more faithful to Scripture than the Catholic answers, and at least as well-represented in the traditions of the Church.

The Protestants did more than out-catholic the Catholics. They also spoke to the deepest needs of sinful souls. I will never forget the moment when, like Luther five hundred years earlier, I discovered justification by faith alone through union with Christ. I was sitting in my dorm room by myself. I had been assigned Luther’s Explanations of the Ninety-Five ­Theses, and I expected to find it facile. A year or two prior, I had decided that Trent was right about justification: It was entirely a gift of grace consisting of the gradual perfecting of the soul by faith and works—God instigating and me cooperating. For years, I had attempted to live out this model of justification. I had gone to Mass regularly, prayed the rosary with friends, fasted frequently, read the Scriptures daily, prayed earnestly, and sought advice from spiritual directors. I had begun this arduous cooperation with God’s grace full of hope; by the time I sat in that dorm room alone, I was distraught and demoralized. I had learned just how wretched a sinner I was: No good work was unsullied by pride, no repentance unaccompanied by expectations of future sin, no love free from selfishness.

In this state, I picked up my copy of that arch-heretic Luther and read his explanation of Thesis 37: “Any true Christian, whether living or dead, participates in all the blessings of Christ and the church; and this is granted him by God, even without indulgence letters.” With these words, Luther transformed my understanding of justification: Every Christian possesses Christ, and to possess Christ is to possess all of Christ’s righteousness, life, and merits. Christ had joined me to himself.

I had “put on Christ” in baptism and, by faith through the work of the Spirit, all things were mine, and I was Christ’s, and Christ was God’s (Gal. 3:27; 1 Cor. 3:21–23). His was not an uncertain mercy; his was not a grace of parts, which one hoped would become a whole; his was not a salvation to be attained, as though it were not already also a present possession. At that moment, the joy of my salvation poured into my soul. I wept and showed forth God’s praise. I had finally discovered the true ground and power of Protestantism: “My beloved is mine, and I am his” (Song 2:16).

Rome had brought me to ­Reformation.