The Bible says Moses wrote down the Law of God and gave it to the children of Israel. It was immediately accepted as authentic by his successor, Joshua, and all God-fearing Jews, down through the centuries.
We have learned from the Bible itself that the “secret” of the spiritual and physical well-being of Israel is that they have access to the Word of God! Whether they hear it or read it, the Word awakens and nourishes their souls and spirits to eternal life.