The hiloula, or yarzeit celebration, for Second Temple era sage Shimon HaTzaddik (Simon the Righteous), began Sunday night at Shimon Hatzaddik's tomb in eastern Jerusalem.
Among those in attendance were Rav Yaakov Yosef and MK Michael Ben Ari of the National Union.
Hundreds more people are expected to reach the tomb during the next 24 hours. Police forces and other forces are providing security for the event.
A Hospitality Tent has also been set up, and food and drink are given to those arriving.