"Catechism means the instruction in which the heathen who want to be Christians are taught and guided in what they should believe, know, do, and leave undone, according to the Christian faith. This is why the candidates who had been admitted for such instruction and learned the Creed before their baptism used to be called catechumenos. This instruction or catechization I cannot put better or more plainly than has been done from the beginning of Christendom and retained till now, i.e., in these three parts, the Ten Commandments, the Creed, and the Our Father. These three plainly and briefly contain exactly everything that a Christian needs to know. This instruction must be given, as long as there is no special congregation, from the pulpit at stated times or daily as may be needed, and repeated or read aloud evenings and mornings in the homes for the children and servants, in order to train them as Christians. Nor should they only learn to say the words by rote. But they should be questioned point by point and give answer what each part means and how they understand it. If everything cannot be covered at once, let one point be taken up today, and tomorrow another. If parents and guardians won’t take the trouble to do this, either themselves or through others, there never will be a catechism, except a separate congregation be organized as stated above."
--Luther's Words, AE53:64-65.