Touching the catechesis of children in the Jewish church, the Old Testament abounds in many explicit commands. In the 12th and 13th chapters of Exodus, God commands the Jews to give particular instruction to their children and families in relation to the institution and benefits of the Passover. In the fourth chapter of the book of Deuteronomy he enjoins it upon parents to repeat to their children the entire history of the law which he had given them. In the sixth chapter of the same book, he requires that the doctrine of the unity of God, and of perfect love to him should be inculcated and impressed upon the minds of their children; and in the eleventh he commands them to explain the Decalogue to their children. Hence, under the Old Testament dispensation, children were taught in the family by their parents, and in the schools by the teachers of religion, the principal things contained in the prophets, viz.: such as respects God, the law, the promise of the gospel, the use of the sacraments, and sacrifices, which were types of the Messiah that was to come, and of the benefits which he was to purchase; for there can be no doubt but that the schools of the prophets Elijah, Elisha, etc., were established for this very purpose. It was also with this design that God delivered his law in the short and condensed form in which it is. “You shalt love the Lord your God with all your heart,” etc., “and your neighbor as yourself.” So also as it respects the gospel; it was briefly comprehended in the promises, “The seed of the woman shall bruise the serpent’s head;” “And in your seed shall all the nations be blessed.” They had, likewise, sacrifices, prayers, and other things which God required Abraham and his posterity to teach their children and families. Hence it is that this doctrine is presented in such a plain and simple form as to meet the capacity of children and such as are unlearned.
In the New Testament we are told that Christ laid his hands upon little children and blessed them, and commanded that they should be brought unto him. Hence he says, in Mark 10:14, “Allow the little children to come to me and do not forbid them for of such is the kingdom of God.” That the catechesis of children was diligently attended to in the times of the apostles is evident from the example of Timothy, of whom it is said that he knew the holy Scriptures from a little child; and from what is said in the epistle to the Hebrews, where mention is made of some of the principal heads included in the catechism of the apostles, such as repentance from dead works, and of faith towards God, of the doctrine of baptism, and of laying on of hands, and of resurrection from the dead, and of eternal judgment, which the apostle terms milk for babes. These and similar points of doctrine were required from the Catechumens of adult age at the time of their baptism, and of children at the time of their confirmation by the laying on of hands. Hence, the apostle calls them the doctrine of baptism and laying on of hands. So likewise the Fathers wrote short summaries of doctrine, some fragments of which may still be seen in the Papal church. Eusebius writes of Origen, that he restored the custom of catechesis in Alexandria, which had been suffered to grow out of use during the times of persecution. Socrates writes thus in relation to the system of catechesis in the primitive church: “Our form of catechesis,” he says, “is in accordance with the mode which we have received from the Bishops who have preceded us, and according as we were taught when we laid the foundation of faith and were baptized, and according as we have learned from the Scriptures,” etc. Pope Gregory caused images and idols to be placed in the churches, that they might serve as books for the laity and children. After this period the doctrine of the church, through the negligence of the bishops and the subtlety of the Roman priests, became gradually more and more corrupt, and the custom of catechesis grew more and more into disuse, until at length it was changed into the ridiculous ceremony which to this day they call confirmation. So much concerning the origin and practice of catechesis in the church.
—Zacharias Ursinus, A Body of Orthodox Doctrine, 2.2.