The three Jewish Pilgrimage Festivals (Pesah, Shavuot and Sukkot) is a continuation of the age old custom of travelling to Jerusalem. In ancient times Jewish pilgrims came to Jerusalem from all over the country or abroad on foot.
Nowadays a formal "priestly blessing" (Birkat Kohanim) is said at the Wailing Wall in memory of the former pilgrimage. A multitude of people assembles and prays from the early hours of the morning in front of the Wall.
The Birkat Kohanim (Aaronic Blessing) is administered by members of the Kohanim, or priestly class, usually on religious holidays. The hands are spread into two “V” shapes:
A kohen (pl. kohanim) is a Jew who is in direct patrilineal descent from the Biblical Aaron, older brother of Moses, with an honored status in Judaism. Another term for the descendants of Aaron are the Aaronites or Aaronids.
For hundreds of years since the period of the Tabernacle, kohanim performed many duties as commanded in Torah. During the existence of the Temple in Jerusalem, kohanim performed specific duties with the daily blessings and festival sacrificial offerings, as example. The Kohen Gadol (High Priest) played a special role during the service of Yom Kippur.
The Blessing, also known as Nesiat Kapayim, (lit. Raising of the Hands), symbolizes the light of the Shekhina, or Presence of God. It is based on a scriptural verse: "They shall place My name upon the children of Israel, and I Myself shall bless them."
The blessing itself is taken directly from that given in the Book of Numbers (6:24-26):
May Adonai bless you and guard you
May Adonai make his face shine upon you and be gracious unto you
May Adonai lift up his face onto you and give you peace.