At the risk of oversimplification, the central concept for Luther was trust, and for Calvin it was obedience, but for the Evangelical Radicals it was discipleship. The Radicals agreed with the magisterial Reformers about justification by faith but they were not willing to stop there. Their concern was about what followed justification - character development, the ethical life, and where love predominates. They criticized bitterly contemporary Catholicism and Protestantism for their lack of emphasis on the regenerate life and love. Karlstadt, one of their leading theologian, while agreeing with Luther about God’s grace, felt Luther had not gone far enough. The Radicals emphasized above all else, discipleship.
O'Reggio, Trevor, "Anabaptists and Discipleship" (2016). Faculty Publications. 1518.