Star of David origin

“But You God are a shield for me…” (Psalms 3:4). David refers here to God as being his ‘shield’. This brings us to the topic of the ‘Magen David’, [lit. shield of David] popularly know as ‘the Star of David’, and regarded as a symbol of Judaism. Strangely, there is no mention of this symbol or its meaning in any authoritative Jewish book.

Rabbi Moshe Feinstein, in Igros Moshe (Orach Chaim Vol. 3, Res. 15) tells us that the most convincing source for this sign is David himself. For it is clear that David did not find security in battle from any armor or shield. Only in God did he find himself securely enveloped, invulnerable from every side - above and below, east, west, north, south, - six directions in all. Thus the six-pointed symbol stands for David’s true shield - God! Rabbi Feinstein concludes that for this reason this symbol, hallowed by centuries of traditional usage, should be respected, because it is meant to symbolize the eternal Jewish faith in God no matter what the adversity.

origin: Psalms - Vol. 1, Artscroll Tanach Series