The ancient Jewish custom of dancing with the closed Torah scroll on Simchat Torah. Since its giving at Mount Sinai in the year 2448 from creation, the Jewish people have dedicated themselves to studying, renewing, and deepening their understanding of the Torah. Wouldn't it be more fitting, on the day of the Joy of the Torah, Simchat Torah, to study it more thoroughly and deeply? "The Torah that Moses commanded us is an eternal inheritance for the congregation of Jacob" (Deuteronomy 33:4). Our sages say that as soon as a child begins to speak, his father should teach him to recite this verse (Talmud Sukkah 42a).
The Torah referred to in the verse is all The Torah. When a student comes up with a new explanation of a concept in the Torah, as long as it's based on the principles of interpretation given with the Torah at Mount Sinai, what they are doing is revealing part of the Torah that Moses commanded us to give; they are not generating something new, nor are they creating a new Torah. The difference between previous and subsequent generations lies in how much Torah was revealed. Therefore, everything that is ever revealed and understood was commanded by Moses at Mount Sinai, from the mouth of God.
The verse teaches us, then, that everything we study, everything we will ever study, and everything we will ever understand, is the Torah that Moses commanded us to give.
According to this explanation, how can it be that our wise men send a father to teach, at least as a hint, to a child who is just beginning to speak, such a profound concept?
The explanation is that in the Torah there are two basic levels: the level that relates to the intellect, where one must understand what one studies, and the essence of the Torah, which is far beyond understanding. The essence relates to the soul of every Jew, regardless of age or intellectual capacity.
This is what the end of the verse refers to when it speaks of the "inheritance of the congregation of Jacob." The concept of inheritance is that, regardless of the heir's status, the inheritance belongs to him; even a newborn child has a right to his father's inheritance.
Even if one wonders, "Why tell this to a child who can barely speak? Wouldn't it be better to wait until they can grasp the idea and then convey it?" the truth is that the foundation of all Torah study is knowing that the essence of Torah transcends intellect. The essence of Torah is that it is the wisdom of God, and He and His wisdom are one. Therefore, just as God transcends intellect, so does His Torah. If this concept is lacking, the very foundation of Torah is missing. That is why it is important for a child, from a very young age, to hear this concept and internalize it.
From this, we will understand the ancient custom of dancing with the Torah on Simchat Torah. If we were to open the book and begin to study it, we would be connecting with the intellectual dimension of the Torah. We would be emphasizing the difference in how people grasp its meaning, since some understand more than others, or in other words, the Torah "belongs" to some more than to others. Therefore, on Simchat Torah, we close the Torah scroll, take it out, clothed in its garments, carry it in our arms, and dance with it, expressing the level of Torah that belongs to everyone, emphasizing that "The Torah that Moses commanded us is the inheritance of the congregation of Jacob" and belongs to us all equally.
Extracted from Likutéi Sijot vol. 4, p. 1165