It is a positive mitzva to assemble all of Israel – men, women, and children – on Sukkot at the end of each Shemita year, during their pilgrimage to the Temple. Sections of the Torah that encourage faith, reverence, Torah study, and mitzva observance are then read to them, as it is written:
And Moses instructed them as follows: Every seventh year, at the time of the Shemita year, at the Festival of Sukkot, when all Israel comes to appear before the Lord your God in the place that He will choose, you shall read this Torah aloud in the presence of all Israel. Assemble (Hak’hel) the people – men, women, children, and the strangers in your communities – that they may hear and so learn to revere the Lord your God and to observe faithfully every word of this Torah. Their children, too, who have not had the experience, shall hear and learn to revere the Lord your God as long as they live, in the land that you are about to cross the Jordan to possess. (Devarim 31:10-13)
The purpose of this assembly, which took place once in seven years, was to raise the honor of the Torah and its commandments. There was no grander, more impressive event than this, in which all of Israel participated – young and old, men and women, and most esteemed of all, the king, who would read from the Torah to the people. This spurred everyone to ask: What is the point of this large assembly? The answer was self-evident: “To hear the words of Torah, which is our foundation, our glory, and our grandeur. This would lead them to speak its great praises and its esteemed glory. They would all be implanted with desire for it, and from this desire they would learn to know God, earn the ultimate goodness, and God would be pleased with their actions” (Sefer Ha-ḥinukh §612).
Every participant benefited greatly from Hak’hel. Those able to study Torah in depth were inspired to increase their study. Those able to listen and understand were inspired to listen avidly to the Torah’s words and to live by them. Children who were old enough to understand listened to the words, and the sanctity of the occasion inspired and encouraged them to study Torah and keep mitzvot. As for those children who were too young to understand, their souls absorbed the tremendous value and incomparable importance of Torah, when they saw that everyone was gathering together to hear it. Their parents were inspired too, recognizing the monumental mission incumbent upon them: to educate their children to Torah and mitzvot (Ramban on Devarim 31:12-13; Maharal, Gur Aryeh, ad loc.; see Harḥavot).
All were obligated in this mitzva, from converts who did not yet understand Hebrew to great sages who knew the entire Torah, for Hak’hel is a reflection of the revelation at Mount Sinai; the entire people must imagine and feel that they are now accepting the Torah directly from God. (See MT, Laws of Pilgrimage Offerings 3:6.)
The Sages ordained that the king read from the Torah to further dignify the event. However, even when there is no king, the king’s voice is weak, or he is a minor, the mitzva is not abrogated. Rather, a very prominent person does the reading – a prince, Kohen Gadol, or great Torah sage. (See: Tiferet Yisrael on Sota 7:8; Minḥat Ḥinukh §612; Ha’amek Davar on Devarim 31:11; R. Eliyahu David Rabinowitz-Teomim (Aderet), Zekher Le-Mikdash ch. 1.)