Rabbi Yaacov Haber
The very first Rashi in the Torah makes the following comment. "Really, the Torah should have begun with Hachodesh Hazeh Lochem (the mitzva of Rosh Chodesh) but a time will come when the nations of the world will call us robbers for taking the land of Israel. At that time we should tell them how the world was crated by God and the whole world is His."
The mitzva of Rosh Chodesh is well into the book of Sh'mos. If the Torah would have started there, we would never have known the story of the creation of the world. We would never have heard of our forefathers, the tribes of Israel, how we descended to Egypt. The story of the Akeidah wouldn't be part of our history. Judaism would have looked completely different. Yet Rashi, with one sweep says, the Torah could have left it all out but for what seems to be a minor consideration an answer for the nations of the world. Seemingly, this is the justification for the whole book of Braishis.
The Talmud (Meggilah 14) asks the following question. We know, that the number of prophets that existed in the history of Israel was twice as large as the number of Jews that left Egypt. This means that there were well over a million prophets in the history of the people of Israel. Yet when we count the prophets in the Bible we find only 48. What happened to the rest?
Answers the Talmud, "A prophecy which will be needed by future generations will be included in the Torah, if it won't be needed by future generations it was not included." I once heard an explanation of this in the name of Rav Elchanan Wasserman, that in order for something to become "Torah" it has to be netzach [eternal]. If the message of the prophets was not needed for future generations then obviously it was not an eternal message, and therefore cannot be included in the Torah.
Rashi (Talmud ibid.) explains the criteria for eternity, "The prophecy is needed for teshuva [repentance] and for horaha [decisions of Jewish law]." If a prophecy teaches us either of these, then it became Torah and therefore was written. If not, it did not get written for inclusion among the books of the prophets and holy writings.
Let us understand this:
1)Teshuva - probably the other million prophets also spoke of teshuva and thereby had an eternal message.
2)Horaha - The Talmud says in Chullin that a prophet had no right to introduce a new halacha to the Jewish people. Law came from Moses and could not be added upon or subtracted from by any Jew, even a prophet. So what, then, was the eternal value of prophecy for halacha?
The Maharatz Chayos asks a similar question. If it's true that a prophet has no ability to create new laws for the Jewish people, how is it that there are many laws which we derive only from the Prophets? Something as basic as gerius [conversion to Judaism] we would know very little about if it weren't for the Book of Ruth. The law that a shochet's knife must be examined before slaughtering is derived from the Book of Joshua. There are many more. The Maharatz Chayos points out that if indeed we were not to learn new halachos from the prophets, much of Judaism would look different.
The answer lies in the following principle. All the laws that the prophets taught us were well known to the people of Israel for generations. These laws were given to Moses orally and passed down through the generations. The prophets never taught new laws. But for some reason, at the time of a particular prophet, it was decided by God through the prophet that the law should transform the Oral Law to Written Law. So the law that had been transmitted orally thus far, now became included in the written Torah. The prophet said nothing new in terms of halacha but rather made Oral into Written.
In the Sefer Niviei Emes, Rabbi Wolf (z'l) writes that he asked his teacher the Chazon Ish to explain this difficult concept. The Chazon Ish replied that oral law becoming written law was indeed an ancient concept, for the Talmud says that Moses received the whole Torah on Mt. Sinai, but that he only wrote down form the beginning until the episode of giving the Torah. Then, for the rest of his life, he prophesied from the Tent of Meeting. It was there that God instructed Moses as to the manner of writing down what he had already known orally. In the words of the Talmud, "God dictated and Moses repeated, then wrote." Hence, says the Chazon Ish, Oral Law was transformed to Written Law?
The question remains exactly what the significance is of having the Oral Law written. The strength of the halacha is not affected by whether it is written or not, and certainly there are many Oral Laws which are better known than Written Laws. Why did God, through his prophets starting with Moses, transfer laws from oral to written?
This can be explained as follows. We find in the Torah that the Torah itself is called Sefer HaBris or the Book of the Covenant. The Ten Commandments are referred to as the "Two tablets of the Bris." Bris means covenant or in simpler terms, contract. The Bris is a two-way agreement between God and the Jewish people. God tells us that if we follow the Torah we will be blessed; if we don't, we will be cursed; if we didn't, we can repent and be forgiven. This is all part of a deal that God made with us when we became the chosen people.
If the Torah is a contract, the Torah must be written. This is clear from the Torah itself. "God said to Moses, write down what I am telling you because what I am telling you constitutes a Bris" (Sh'mos 34:27). Rashi quotes the Talmud that from here we learn that the Oral Law must not be written and the Written Law should not become oral. Today, we write down the Talmud (which is Oral Law) because of extenuating circumstances for which the Torah itself permits its writing.
According to this, it becomes very clear that many of the things which Moses heard on Mt. Sinai and passed on to the people of Israel were eventually decided by God to become part of the agreement. These things were not only directives as per behavior, but were an actual part of our contract as Jews. The prophets never taught new halachos, but through their prophecy they knew what was to become part of the Bris and what wasn't.
Perhaps this could explain that first Rashi in the Torah. Certainly, if the Torah would have begun at "Hachodesh Hazeh Lochem" we still would have known all the stories of creation and of our forefathers. It would have and could have been Oral Law. In fact, many stories of Abraham are not written in the Torah (e.g. being thrown into a fiery furnace). By the fact that it was written in the Torah, however, we know it is significant - not only for its historical value, or even in the relation to its holiness, but because it is actually part of the contract between God and Israel.
In practical terms this means that the behavior of our forefathers is credited towards our deeds, and that we have an obligation to live up to that which was set forth for us by our forefathers. If the nations of the world, says Rashi, tell us we are thieves insofar as we take the land of Israel undeservedly, we should show them the contract we have with God and that it was all part of the deal. This is the essence of a "prophecy for all times".