The Oral Torah Explained: Why It Was Given Alongside the Written Torah

How can we be certain that at Mount Sinai God truly gave the Jewish people not only the Written Torah but also the Oral Torah? Why did God want there to be an Oral Torah rather than giving everything in written form?

Following are a few verses from the Written Torah that testify to the existence of the Oral Torah and to God’s command to learn the Torah through the sages:

1. “These are the statutes, the ordinances, and the laws that the Lord gave between Himself and the children of Israel at Mount Sinai by the hand of Moses” (Leviticus 26:46); and “And you shall caution them regarding the statutes and the laws, and make known to them the way in which they must walk and the deeds they must do” (Exodus 18:20).
   These verses indicate that at Mount Sinai two Torahs were given — the Written Torah and the Oral Torah.

2. “And the Lord commanded me at that time to teach you statutes and ordinances for you to perform” (Deuteronomy 4:14).
   The Written Torah itself records that God commanded Moses to teach the people the laws orally, not to only hand them a written scroll.

3. “The Lord said to Moses: Come up to Me on the mountain and remain there, and I will give you the stone tablets, the Torah, and the commandment that I have written, to teach them” (Exodus 24:12).
   At Mount Sinai Moses received both the tablets (the Ten Commandments), the Written Torah, and the “commandment”, which refers to the Oral Torah, containing explanations and practical instructions for fulfilling the commandments. The verse makes clear that the way to convey the mitzvot is through teaching and guidance.

4. “And it was, when Moses had finished writing the words of this Torah in a book, until their completion…” (Deuteronomy 31:24).
   The Written Torah tells us that the scroll of the Torah was handed to the Israelites only at the end of Moses’ life. Until then, the Torah was taught and transmitted orally, which is proof that Oral Torah study preceded the giving of the complete Written Torah.

Moses ascended Mount Sinai for 40 days and nights. During that time, God taught him all the interpretations, layers, and depths of the Torah (the Oral Torah). Throughout the Israelites’ years in the desert, Moses wrote down the Written Torah according to God’s word, but the Oral Torah, with all its rules and details, was taught directly to the elders and sages, who then transmitted it to the people.

Why Not Write It All Down?

Why was an Oral Torah necessary? Why didn’t God give one Torah, entirely written, containing everything?

1. The “Safe Combination” Isn’t Written Down
   The Midrash explains: “The Holy One foresaw that idol worshippers would one day translate the Torah into Greek and claim that they too are Israel. God said to the nations: I only recognize the one who holds My secrets. What are those secrets? The Mishnah (Oral Torah)” (Yalkut Shimoni on Hosea).
   God knew there would come a time when idolaters would falsely claim that God had broken His covenant with Israel, made a new covenant with them, and added to the original Torah. The safeguard against such a claim is that the explanations and secrets of the Torah were given only to the Jewish people via oral tradition. The Oral Torah is the “code” needed to truly understand the Written Torah, which is often brief, cryptic, and sealed. Without this “code,” the text remains inaccessible.

   By analogy, if you have a credit card, you wouldn’t write the PIN on a slip of paper inside your wallet because if the wallet were lost, anyone could access your account. Instead, you memorize the code and share it only verbally with trusted family. Likewise, God gave the crown jewel to His children, Israel. To ensure it would remain uniquely theirs, He kept the true understanding in oral form.

2. Learning From the Greats
   God wanted Torah knowledge to pass from scholars to students, from parents to children. Without guidance from someone fully versed in its depths, one could easily misunderstand. Thus, the Torah was intended to be transmitted orally from generation to generation through direct teaching.

3. Keeping It Relevant
   Times change, and new situations arise requiring halachic rulings relevant to the current reality. The Oral Torah contains general principles enabling the sages of each generation to rule on new cases. Many modern questions, such as determining the end of a fast for someone flying across time zones, or whether a Shabbat timer can be set for an iRobot to clean the floor, are addressed through these principles, even if not mentioned explicitly in the Written Torah.

   The very word halacha (“law”) comes from the root “to walk” or “to go,” symbolizing its application alongside a dynamic, changing reality. A Torah written entirely with all final rulings could not address evolving questions.

   Rabbi Joseph Albo (Sefer HaIkkarim, 3:23) wrote: “It is impossible for God’s Torah to be complete in such a way that it suffices for all times, because new details constantly arise in human affairs… Therefore, general principles were given to Moses at Sinai, alluded to briefly in the Torah, so that the sages of each generation could derive new details as needed.”

4. Keeping It Alive, Not on the Shelf
   If the entire Torah were written, it might sit on a shelf, consulted only when a specific question arises. The Oral Torah compels continuous study, discussion, and living connection.

5. An Index to Infinite Details
   The Written Torah is like an index containing the basic principles, but not all the details. The Oral Torah fills in the gaps. Many commandments in the Written Torah are stated briefly without explanation:

   • “You shall dwell in booths for seven days” — what is a sukkah? How is it built?

   • “Bind them as a sign on your hand” — what do tefillin look like, where are they placed, and what is written inside?

   • “Write them on the doorposts of your house” — what exactly is written in a mezuzah?

   • “Slaughter [animals]” — how is kosher slaughter performed?

   • “Do not do work on the Sabbath” — which activities are forbidden?

   All 613 commandments appear in the Written Torah, but none come with complete instructions. The Oral Torah provides the full, detailed guidance necessary to fulfill them.

The absence of practical details in the Written Torah is itself proof that alongside it, God gave an Oral Torah. Without the Oral Torah’s explanations, the Written Torah would remain sealed, and its commandments could not be fulfilled.