Thousands flocked to the Western Wall Plaza in the Old City of Jerusalem Thursday morning for a special holiday service of the Priestly Blessing (Birkat Hakohanim) for the Passover festival.

The morning prayer service began at 8:45 a.m., with the mass Priestly Blessing slated for 9:30, followed by Mussaf services at 10:15 and the second Priestly Blessing at 10:30.

Rabbi of the Western Wall Shmuel Rabinowitz and the Chief Rabbis of Israel, Rabbis Yitzhak Yosef and David Lau, will join in the festivities and address the gathering after the prayer services have been completed.

The blessing is taken from the book of Numbers and is recited by Kohanim every day in Israeli synagogues, with the priests, faces covered with prayer shawls, facing the congregation holding their hands out in a way passed on from generation to generation. Traditionally, the members of the congregation lower their heads and do not look directly at the Kohanim as they are blessed.

In the Diaspora, it is said only on festivals. On Sukkot and Passover, when there are intermediate days that allow for driving and microphones, the tradition of having a mass blessing with a large number of Kohanim at the Kotel was instituted.

The words of the biblical blessing: "May the Lord bless you and keep you, May He shine His face upon you and grant you grace, May He turn His face to you and grant you peace" were found in silver amulets unearthed in an ancient 6th century B.C.E. burial site on Katef Hinom, at what is now the Begin Center in Jerusalem, opposite the Old City, by archaeologist Gabi Barkai.

For a live feed of the Western Wall Plaza, click here.

Video feed courtesy of The Western Wall Heritage Foundation