Hakhel

The term Hakhel (Hebrew הקהל) refers to a biblical commandment of assembling all Jewish men, women and children, as well as "strangers" to assemble and hear the reading of the Torah by the king of Israel once every seven years.

Originally this ceremony took place at the site of the Temple in Jerusalem during Sukkot in the year following a Seventh Year. According to the Mishna, the "commandment to assemble" (Hebrew: מצות הקהל mitzvat hakhel) was performed throughout the years of the Second Temple era and, by inference, during the First Temple era as well. The biblical mitzvah of Hakhel is only in effect when all the Jewish people reside in Israel. In the 20th century, the Lubavitcher Rebbe, Rabbi Menachem M. Schneerson, repeatedly encouraged all Jews to utilize the Hakhel year to assemble men, women and children and encourage each other to increase in Torah observance and study, and foster an environment of fear of G‑d.

The Hebrew Hiphil verb haq'hel (Hebrew: הקהל, "assemble"), from which comes the term mitzvat hakhel, is used in Deuteronomy 31:10-12:

"At the end of every seven years, at an appointed time, in the Festival of Sukkot [following] the year of Shemitah. When all Israel comes to appear before the Lord, your G‑d, in the place He will choose, you shall read this Torah before all Israel, in their ears. Assemble the people: the men, the women, the children, and your stranger in your cities..."

According to the Mishnah, the ceremony was conducted on the first day of Chol HaMoed Sukkot, the day after the inaugural festival day, on behalf of all the Jews who participated in the pilgrimage to Jerusalem. Trumpets would sound throughout Jerusalem (Tosefta) and a large wooden platform would be erected in the Temple in the court of the women (Hebrew: ezrat hanashim עזרת הנשים). The king would sit on this platform and all in attendance would gather around him. The hazzan haknesset (החזן הכנסת, "servant of the synagogue") would hand the Book of the Law to the rosh haknesset (ראש הכנסת, "archisynagogue"), who would hand it to the deputy kohen gadol, who would hand it to the High Priest, who would present it to the king. According to the Sefer Hachinuch, the king would accept the sefer Torah while standing, but could sit while he read it aloud. The rest of Israel were required to stand, which led to Jeroboam's revolt.

...
Wikipedia