The
Star of David Necklaces is a symbol closely associated with Judaism, but it wasn't always symbolic of the Jewish people. While the hexagram shape has become the symbol on the flag of Israel and has come to be closely connected with Judaism since the sixteenth century, it doesn't find its origin specifically with the Jews or the Bible. Made of two full triangles printed atop one another in opposite directions, this symbol has become the common one for use when referring to Jews despite the existence of other Jewish symbols such as the menorah, possibly due to the ease of printing it on a printing press.
The name of the symbol, however, or originates in the Bible, when referring to the Shield of David, which is the Hebrew and Yiddish name for the star.
Magen David (מגן דוד) or Mogen Dovid means shield of David and is the way the star is called in Hebrew and Yiddish. Theoretically, King David had this symbol on his shield when he went to battle, and he was known to go fight on the front line with his troops, so this could have been a symbol that signified the leadership of Israel in that way. The use of this term to describe the hexagram star dates back to the 17th century and the term shield of David is found in the Siddur.
In the 19th century in eastern Europe, in countries such as Czech Republic, Austria and possibly parts of Southern Germany, and centering on Prague, there came a desire of the Jews of the area to have a symbol that could be recognized as theirs, similar to the Christian cross, and the Star of David was adopted for the purpose. Only after the 19th century, however, did the practice spread to other parts of the world and become the widespread accepted symbol of Judaism.
The historical connection of the hexagram and the Jewish people is extensive if we also consider its use in decoration. The symbol is found decorating the carpet page of the oldest known text of the Masoretic text of the Bible, the Leningrad Codex. It also decorates a tanach manuscript belonging to Spanish Rabbi Yosef bar Yehuda ben Marvas, in 1307, and is on the cover of a 1512 Siddur from Prague, along with the text: " "He will merit to bestow a bountiful gift on anyone who grasps the Shield of David."
There are potential Kabbalistic ties to the hexagram shape as well, although it is commonly believed that the Kabbalic writings refer to parallel triangles rather than opposite directions of each other.
David Wolffsohn of the early Zionist movement brought the Star of David symbol into the design of the flag that eventually became that of the state of Israel, with blue stripes on white background to represent the Tallit prayer shawl worn by the Jews at prayers, and the Star of David in the center, as a symbol of Zionism and the Jewish people, a flag to replace the unpopular design Theodore Herzl was using up until that point.
During the holocaust, the Star of David symbol was used to identify Jews for persecution, but it had the effect of bringing them together under the symbol to resist the oppression they were under as well, and has been adopted as the main Symbol of Judaism despite the use in the Holocaust.
Now, the symbol is used in all sorts of things having to do with Judaism and Israel, and is the symbol of Israeli sports teams and found in many Judaica items around the globe.