The Magen David Usually, when we think about a "Magen David," we imagine a six- pointed star, the "Star of David". In fact, the Talmudic reference has nothing to do with a star at all. Pesachim 117b; Rabbah b. Shila said: [The formula] in Prayer is who causes the horn of Salvation to spring forth,’ while that of the haftarah is the shield of David.’ And I will make you a great man, like the name of the great ones [that are in the earth the earth]. (II Samuel 7:9) R, Joseph taught: that alludes to the fact that we say ‘the shield of David.’
When Theodor Herzl looked for a symbol for the new Zionist movement, he chose the Star of David because it was so well known and also because it had no religious associations. In time, it appeared in the center of the flag of the new Jewish state of Israel and has become associated with national redemption. During the Holocaust, the Nazis chose the *yellow star as an identifying badge required on the garments of all Jews. After the war, Jews turned this symbol of humiliation and death into a badge of honor. Today, the Star of David is the most popular and universally recognized symbol of the Jewish People. In his seminal work entitled the Star of Redemption (1912), Franz Rosenzweig framed his philosophy of Judaism around the image of the Jewish star, composed of two conceptual "triads," which together form the basis of Jewish belief: Creation, Revelation, and Redemption; God, Israel, and World. On the popular level, Jews continue to use the Jewish star as it was used for centuries: as a secularized symbol of Jewish identity.
In the middle ages, Jews often were required to wear badges to identify themselves as Jews, much as they were in Nazi Germany, but these Jewish badges were not always the familiar Magen David. For example, a fifteenth century painting by Nuno Goncalves features a rabbi wearing a six-pointed badge that looks more or less like an asterisk. In the 17th century, it became a popular practice to put Magen Davids on the outside of synagogues, to identify them as Jewish houses of worship in much the same way that a cross identified a Christian house of worship; however, I have never seen any explanation of why this symbol was chosen, rather than some other symbol. The Magen David gained popularity as a symbol of Judaism when it was adopted as the emblem of the Zionist movement in 1897, but the symbol continued to be controversial for many years afterward. When the modern state of Israel was founded, there was much debate over whether this symbol should be used on the flag.
Today, the Magen David is a universally recognized symbol of Jewry. It appears on the flag of the state of Israel, and the Israeli equivalent of the Red Cross is known as the Magen David Adom.