The Ushpizin are the seven hidden hosts who, according to Jewish lore, visit each succah during the seven-day festival. This refers to Abraham, Isaac, Jacob, Joseph, Moses, Aaron and David. The origin of this visitation can be found in a verse of Zohar,

"When a person is seated in his succah, Abraham and six distinguished visitors partake of his company."

Each in turn ushers the others into the succah during the subsequent days of the holiday.

The custom prescribes that every evening the attending host be approached with a different request:

"May it be Your will, my G-d and the G-d of our forefathers that the Divine presence rest upon us...I hereby invite our most valued hosts, Abraham...."