If, however, the origin of the office of teacher is to be understood in tis way, then it immediately becomes clear what the basic task of a teacher was: the interpretation of the Holy Scripture. The entire New Testament bears witness to the fact that the interpretation of the Septuagint, the brining of scriptural proof for the Messiahship of Jesus (in the manner in which the Scripture-expert Paul carried it on after his conversion, at first in the synagogues of Damascus––Acts 9:20, 22) was one of the most important tasks of the growing church. For this task the office of Spirit-filled teachers was needed. For the church knew from the beginning that only the Holy Ghost can teach the correct understanding of the Scripture. But the interpretation of the Septuagint was not only a necessity for theological apologists and for missionary instructions, but belongs also in the Service. In congregations of Gentile-Christians, which consisted in part of people who had up to that time visited the synagogues as “God-fearing men,” thus interpretation took the place of the synagogual interpretation of Scripture. If the early Christian teachers are the successors of the teachers of the Hellenistic synagogues––indeed if, like Paul, they to an an extent received their education in this synagogue and had served in this synagogue, then we understand the fact that in the ancient Christian writings that go back to such teachers the connection with Jewish interpretation of the Scripture is extraordinarily great. No matter how far the example of the synagogue extended its effect, in any case it is the explanation of the Scripture, the interpretation of the written Word of God which was the unique, essential task of this office.
In so far then as the interpretation of Scripture coincides with oral preaching, the function of the prophet and of teacher coincide; and in so far both are not to be separated from the apostolic proclamation of Christ, they are connected with the office of an apostle. Thus all three offices are to be understood in their individuality and in their indissoluble intertwinedness. All three are “service of the Word” (Dienst am Wort); all three want to “speak the Word of God,” But each of the three has to do with a specific form of the divine Word: with the Word-Made-Flesh, with the Word which today speaks through human mouths, with the written Word. An apostle bears witness to the Incarnation of the Word. By the mouth of a prophet God speaks today. A teacher interprets the written Word of the Bible. In so far, however, as the three forms of the Word of God are forms of the one Word, the three offices of apostle, prophet, and teacher are one. They are the roots from which the one office of the church, the office of the preaching of the Gospel, has grown.
Scripture and the Church: Selected Essays of Hermann Sasse
edited by Jeffrey J. Kloha and Ronald R. Feuerhahn