The Hamsa in Sephardic Culture
from “Hamsa” by Menachem Wecker
The hamsa has been variously interpreted by scholars as a Jewish, Christian, or Islamic amulet, and as a pagan fertility symbol…it is recognized today as a kabbalistic amulet and as an important symbol in Jewish art…As the references to Fatima (Mohammed’s daughter) and to Miriam (Moses’ sister) suggest, the amulet carries significance to both Jews and Muslims. One of the most prominent early appearances of the hamsa is the image of a large open hand which appears on the Puerta Judiciaria (Gate of Judgment) of the Alhambra, a 14th century Islamic fortress in southern Spain.
It would not be unusual for an Islamic symbol to find its way into Sephardic Jewish culture, which flourished alongside Islam. However, amulets are somewhat problematic in Judaism. Still, the Talmud refers on several occasions to amulets, or kamiyot, which might come from the Hebrew meaning “to bind.” One law allows for carrying an approved amulet on the Sabbath, which suggests that amulets were common amongst Jews at some points in history. (Shabbat 53a, 61a)…
It is difficult to pinpoint the exact time when hamsas emerged in Jewish culture, though it is clearly a symbol of Sephardic nature. Jews might have used the hamsa to invoke the hand of God, or to counteract the Evil Eye with the eye embedded in the palm of the hand. Some hamsas contain images of fish, in accordance with Rabbi Yose son of Hanina’s statement in the Talmud that the descendents of Joseph, who received Jacob’s blessing of multiplying like fish in Genesis 48:16, are protected from the evil eye like fish. He explains: “the water covers the fish of the sea so the eye has no power over them (Berakhot 55b).”
Other icons besides eyes and fish have also found their way into the hamsa, including the Star of David, prayers for the traveler, the Shema, the blessing over the house, and the colors of red and blue, both of which are said to thwart the Evil Eye.
Hamsas still play a role in some Sephardic rituals today. During the henna ceremony, when brides are decorated in the preparation for their wedding, brides may wear a hamsa around their neck to ward off the evil eye.
SOURCE: http://www.myjewishlearning.com/beliefs/Issues/Magic_and_the_Supernatural/Practices_and_Beliefs/Amulets/Hamsa.shtml

