Martin Chemnitz is so much fun to read, especially his Examination of the Council of Trent. The first volume of the English edition includes his teaching on Sacred Scripture and Tradition. He explains why unwritten tradition, although much of it may be true, cannot be relied on to settle doctrinal disputes and controversies. He begins by talking about the Old Testament Scripture and its relationship to patriarchal tradition. These are a summary of his main points:
1. Originally doctrine was transmitted orally.
2. The Word of God was not kept pure by the traditions of the living voice.
3. God often restored the purity of His Word through special revelations to His appointed patriarchs and prophets.
4. Doctrine was continually corrupted by those whom He had appointed and who had the duty of preserving it.
5. Therefore God set down His Word in writing through Moses in order to preserve once and for all those doctrines given to the patriarchs that were necessary for the posterity and faith of His people. Once that Word was inscripturated, it became the norm, rule, and standard by which all other doctrines, traditions, and teachings would be judged. He cites numerous examples of how the kings and prophets, when settling disputes and controversies, always appealed not to the traditions preserved in the memories of the people but to the Book of the Law.
Chemnitz does not deny the possibility that many of the teachings of the patriarchs lived on in the memory of the people. But these were to be rejected if they did not agree with the written Word.
The same thing can be said about the Apostolic Scriptures. Already at the time of the Apostles it was evident that the Word was being corrupted by some teachers. So, once again, God set forth in writing that which was necessary for the faith and posterity of the Church so that His pure Word might be preserved. Did the Apostles preach and teach much more than what is contained in the New Testament? Certainly no one would deny this any more than we would deny the fact that Isaiah probably preached much more than is contained in 66 chapters. But once that Word was written down by the “finger of God” (The Holy Spirit) it became the rule, norm, and standard by which all other unwritten traditions must be evaluated and judged.