All doctrine must be derived from Holy Scriptures. It is not permissible to add or subtract anything (Deut. 4:2 and 12:32). It must be manifested to the people in these ways: first, by the reading of Holy Scriptures; next, by their interpretation, but one which has specifically been derived from the Holy Scriptures themselves; then, by the sound teaching of religion, i.e., by a lucid explanation and a sure confirmation of the dogmas of our faith; then, by pious exhortations, admonitions, reproofs, and testimonials taken from the same Scriptures; after that, by the religious instruction of the ignorant, and by repetition of what has been heard from the doctrine of Christ; further, if certain persons have difficulty with certain texts of Christian doctrine, or even contradict them, by holy conversations and disputations by which the doctrine of Christ may be more fully explained to the weak and the more firmly asserted against dissidents; lastly, also by private teaching, exhortation, consolation, and correction.
We read that Christ, the prince of the churches, the shepherd and teacher, observed all these things religiously in the ministry of teaching the gospel. For in the synagogue at Nazareth, when The Book of Isaiah the prophet had been given to him, he read something from it, which he thereupon interpreted, and derived salutary doctrine and a lesson from it (Luke 4:16-17). All the Evangelists have testified abundantly how prompt he was in responding not only to those who asked something about the doctrine of salvation for the purpose of learning, but also to those who openly attacked him and his teaching and plotted to find an occasion for blaming him.
But with what religious spirit the apostles followed this example of the Lord, Luke has testified to in Acts when, in the synagogue at Pisidian Antioch, so he recalls, Paul and Barnabas had a chance to exhort the people; after the reading of Moses and the prophets, they delivered a sermon about Christ derived entirely from the Holy Scriptures (Acts 13:14-43). That Paul showed himself quick to discourse about the doctrine of the gospel and to prove it to all, even by religious disputes and conferences, is abundantly obvious from the fact that immediately following his conversion he embarrassed the Jews by disputing in the synagogues of Damascus, showing from the Scriptures that the Lord Jesus is the Christ (Acts 9:20-22). Nor did he hesitate to dispute with the Epicureans and Stoics at Athens about the doctrine of the gospel (Acts 17:18 ff.).
Certainly no doctrine must be handed down and confirmed so accurately by every available method of teaching as the doctrine of eternal life. Even now all faithful professors of the learned disciplines are ready, in addition to interpreting their authors and teaching publicly what they mean, to explain and confirm that same doctrine more fully to the dull-minded in appropriate conferences and disputations, and also to defend and safeguard them more completely against adversaries.
In accordance with the same common diligence of true teachers, everyone must acknowledge how useful it is, and how necessary, for the more unlearned to be taught by the catechism, whether they are children in age or in the amount of sense they have, so that they may be individually instructed by appropriate questions and answers in the fundamentals of our religion. For what faithful schoolteacher, or teacher of any discipline or art, thinks that it is enough to have recommended good authors to his students, or to have handed on the rules of disciplines and arts, and does not also examine his students on what he has explained or shared in an effort to get them to learn better, questioning them to see how each has understood the matter and giving them an opportunity to ask him about anything that has not been well enough understood. For, as I just said, there is no doctrine which ought to be learned more diligently than the knowledge of eternal salvation. Therefore with burning zeal and diligent care we must produce teaching methods and catechisms in the churches which surpass those used Elsewhere.
Both the synagogue and the early Church exhibited a singular concern for this kind of catechizing. Also, our Lord Jesus Christ took part in something of this sort when at twelve years of age he remained in Jerusalem without the knowledge of his parents. For so Luke writes of him: “They found him sitting in the Temple in the midst of the teachers, both listening to them and asking them questions, and all who heard him were astonished at his understanding and his responses” (Luke 2:46-47). Jesus, therefore, then listened. To whom? Undoubtedly to the teachers, who were catechizing him and the other boys. For in all things he always exhibited utmost moderation; he both asked them questions and answered them when they asked him questions, which is really the nature of catechizing. Thus the ancient churches always had certain ministers assigned to this duty of catechizing; they were called catechists. We read in the fifteenth chapter of the sixth book of the Church History that Origen was one of those in the church of Alexandria and also Heraclas. In other churches, there were others. By these methods Christian teaching is publicly administered wherever Christ has firm sovereignty.
Those pastors and teachers of the churches who want to fulfill their office and keep themselves clean of the blood of those of their flocks who are perishing should not only publicly administer Christian doctrine, but also announce, teach, and entreat repentance toward God and faith in our Lord Jesus Christ, and whatever contributes toward piety, among all who do not reject this doctrine of salvation, even at home and with each one privately. Concerning this, one should read and piously ponder the speech that Saint Paul made to the Ephesus elders whom he had summoned to Miletus when he was setting out for Jerusalem (Acts 20:17 ff.). For the faithful ministers of Christ should imitate this their master and chief shepherd of the churches, and seek most lovingly themselves whatever has been lost, including the hundredth sheep wandering from the fold, leaving behind the ninety-nine which remain in the Lord’s fold (Matt. 18:12).
How promptly the Lord dispensed heavenly doctrine, even at home and individually, the Evangelists testify abundantly. For he spared no pains to teach the catechism to that Samaritan woman even though she had not led a pure life; indeed, he was so eager in spirit to instruct that woman unto salvation that although he was tired and hungry, he nevertheless refused to take the food brought to him by his disciples, saying that he had other food to eat, namely, to procure the salvation of that miserable woman (John 4:10-34).
So also the Evangelists recall that he entered private homes not at all unwillingly, and not only of friends and true disciples, but also of sinners and Pharisees, who were in the habit of reviling all that he said and did, and he revealed the doctrine of eternal life in their company also, by denouncing the sins of the hosts as well as those of the guests and by explaining the mysteries of his Kingdom (Luke 10:38-42; Matt. 9:10-13; Luke 7:36-50; 14:1-24). From these things, therefore, it can be adequately seen how doctrine must be administered, and this is the first function of the sacred ministry.