Elector Frederick III, a friend of the Protestant Reformation writes the preface to The Heidelberg Catechism.
January 19, 1563 – “A good catechism sets out the core truths that Christians believe. It is usually arranged in the form of questions and answers so that it can be easily remembered. A catechism might ask, ‘What is true faith?’ and answer, ‘True faith is not only a knowledge and conviction that everything God reveals in his Word is true; it is also a deep-rooted assurance, created in me by the Holy Spirit through the gospel, that, out of sheer grace earned for us by Christ, not only others, but I too, have had my sins forgiven, have been made forever right with God, and have been granted salvation.'” – Christianity.com, May 3, 2010