What is Hakhel?
In ancient Israel, every seventh year was a Shemitah ("sabbatical") year. For an entire year, the nation's economy came to a standstill as all farmers and agrarian workers abandoned their fields and flocked en masse to the study houses where for a full year they focused on their spiritual, rather than physical needs.
Now, at the onset of the eighth year (the first in the new seven-year cycle), the nation is ready to head back to the fields and orchards. But first, on the second day of the holiday of Sukkot, sixteen days into the new year, all gather in the Holy Temple for a dose of inspiration. Inspiration to tide them over for the next six years, most of whose time would be spent in business endeavors.
The biblical mitzvah of Hakhel is only in effect when all the Jewish people reside in the Holy Land. Nevertheless, the Lubavitcher Rebbe repeatedly encouraged all Jews to utilize this auspicious time 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.