For decades, conservative Christians opposed to homosexuality cited the Bible scholarship of Richard B. Hays, the dean of Duke Divinity School, who provided a full-on argument from Scripture against gay relationships. “Homosexuality is one among many tragic signs that we are a broken people, alienated from God’s loving purpose,” Mr. Hays asserted in his book “The Moral Vision of the New Testament” (1996), which was read by a generation of seminary students. Then, last year, Mr. Hays released a thunderclap into the evangelical world by recanting his earlier views and asserting that a deeper reading of the Bible revealed that...