Primary Motivation. Christian humanists were eager for church reform, but they were surprised by the direction it took when the German cleric Martin Luther emerged as its leader. He accepted much of the humanist program, but he found infuriating its indifference to the importance of precise definitions of doctrine and sense that human imperfection made finding truth impossible. Luther emerged from his youthful confusion and doubt over how he or anyone could be saved with a profound conviction that he had found the correct answer. This confidence that they had found the truth of the gospels marked all the major Protestant leaders and suggests that the primary motivation behind the Reformation was the reform of doctrine, not the reform of clerical abuses, as much as the first Protestants complained about them.

Importance of Faith. Young Luther engaged in a ferocious...