The receiving of the Torah was the most significant event in the history of the Jewish people. Not only does the Yom Tov of Shavuos revolve around the experience of Har Sinai, but we are also commanded to never forget the events that occurred on that first Shavuos. We are given a two-fold commandment, "Do not forget what you have seen...and transmit them to your children and grandchildren" (Devarim 4:9.) What precisely must we be careful not to forget? What exactly are we to impart to the next generations?
We are taught (Pirkei Avos 3:10) that one must be exceedingly careful not to forget what one has learned, and one who forgets even one word of what he has learned is in violation of the prohibition mentioned above. Although one who tries to retain the information studied and doesn't succeed does not violate this prohibition, the essence of this halacha is to emphasize the significance of remembering as much Torah knowledge as possible. The corollary of this prohibition is the positive commandment to transmit all of our knowledge to our children.
There is a dispute between Rabbeinu Yona, the Rambam, and the Ramban as to the precise nature of this dual commandment. Rabbeinu Yona in his commentary to Pirkei Avos explains why the Torah insists that we not forget what we have learned. One who forgets will inevitably commit errors in his mitzvah observance. According to Rabbeinu Yona the Torah is highlighting the role of talmud Torah as the prerequisite for the proper observance of the mitzvos. We are required to do everything in our ability to maintain proper observance for ourselves and our children, and his begins with a thorough knowledge of the Torah.
The Rambam (Hilchos Talmud Torah 1:10) emphasizes a different aspect of talmud Torah concerning the prohibition of forgetting. The Rambam cites the prohibition against forgetting one's learning as the source that one must learn until the end of one's life. Rav Moshe Feinstein explains that the Rambam is addressing the dimension of talmud Torah as an end in it and of itself. How much must one learn to fulfill this mitzvah properly? One must learn the entire Torah. One who forgets any Torah must continue to learn because otherwise this mitzvah is not fulfilled in its entirety. Thus, the Rambam saw in this passuk the source for an independent, never ending obligation to study Torah, not just as a way to fulfill other mitzvos. Only if we dedicate ourselves to maintaining a complete mastery of Torah as a goal in it of itself can we impart this knowledge properly to our children.
The Ramban in his Sefer Hamitzvos (prohibition two not mentioned by the Rambam) interprets this dual obligation as focusing on the general experience of Har Sinai rather than addressing forgetting a specific part of the Torah as the Rabbeinu Yona and the Rambam did. The Ramban elaborates as to why the nature of the Har Sinai experience must be constantly remembered. It was only this experience which enables the Torah to remain eternal in our eyes. If we would have only received the Torah from Moshe without seeing Hashem's presence revealed on Har Sinai, we could potentially be led to believe by a subsequent navi that a new Torah had been given. We who saw with our own eyes that Hashem gave us this Torah are certain that this Torah will remain eternal. We must constantly strengthen our own faith in this principle and transmit it to our children.
As we celebrate that monumental day at Har Sinai, we have to once again commit ourselves to all aspects of kabalas haTorah. We must constantly strive to reach greater heights in talmud Torah enabling ourselves and our children to properly observe the mitzvos. Talmud Torah must also be an independent goal; mastering as much Torah as we can must be an absolute priority for ourselves and our children. An absolute commitment to the eternal truth of the Torah must be maintained. This cornerstone of Jewish belief must be guarded and transmitted properly to the next generation.