Internal Logic of the Torah - refutes extra-Scriptural Law

Exodus Chapter 24

4 And Moses wrote all the words of the LORD, and rose up early in the morning, and builded an altar under the mount, and twelve pillars, according to the twelve tribes of Israel.



This structure is repeated several times in the Torah, as well as in the book of Joshua.

There are those who claim that not only was there a Torah that was written by Moses, but also another body of Law, that is not included in the Written Law.  This is called, by Orthodox Rabbinic Judaism, the "Oral Law".  The reason it is called Oral, is because it is believed to have been transmitted verbally from generation to generation, without it being written down.   (It was written down eventually in the Mishnah and Talmud).

The Torah has its own internal logic.  The logic of the above verse is telling us that Moses faithfully and accurately recorded "all" the words of the Lord in a Scroll - the Sefer Torah.  
It is simple mathematical logic - if All the words of the Lord (prophetically given to Moses) were written down, that  is 100% of the Divinely revealed Law.  That means, there is 0% remaining to be transmitted orally or otherwise.

Since we see this statement several times throughout the Torah, we can be certain, 100%, that there was no additional Prophecy, law or revelation given to Moses, outside what was written in the Torah.

It does not matter if it is inconvenient , it does not matter if my great-great grandfather's learned brother, of blessed memory,  was the Rabbi of his community. It also does not matter that Maimonides of blessed memory  was an absolute intellectual giant in Philosophy, Astronomy, Medicine, and Talmud.   It does not matter that the Holy orthodox community is successful, and has many yeshivot and synagogues. None of these change what is written in the Torah.

All that matters is what is certain - it is certain that the Torah tells us that 100% of the Torah revealed to Moses by Y-H-V-H  was written in the Sefer Torah.