There is no concrete evidence that the Star of David is related to religion. In Hebrew it's called Magen David - David's Shield, it it could simply be that King David's shield had this shape. Being the most popular king and warrior that we ever had, it would make sense that the shape became popular However there are lots of theories about the connection between the shape and religion - many of them can be found at http://www.answers.com/topic/star-of-david-1
The Star of David, or Magen David, is not Jewish in origin. In the Hellenistic world, hexagrams like this were used by all religions. In the Middle Ages, Jews, Christians and Muslims used them to ward off demons and fires.
In the fourteenth century, Jewish mystical texts began associating the hexagram image with the shield of God used to protect King David. The Star of David first appeared on a Jewish flag in Prague in 1527 when Enlightenment Jews needed a symbol equivalent to the cross to indicate that Judaism was a religion, not a race.
This being said, the Star of David is not a religious image in Judaism, it is a civic symbol.
If I understand your question to mean, if the Cross is a symbol in Christianity which refers to sacrifice of God for humanity in which Christians believe is the way by which humans can be saved, what role does the Star of David play in Judaism?
The first problem with the question is the misnomer. The Hebrew is not Kochav David (Star of David) but Magen David (Shield of David). David was an Israelite King and a renowned warrior. The Shield of David is the emblem on the shield he brought with him into battle with Canaanite Tribes and the Philistines. It became a symbol of the protection that God gave to the Israelite Kingdom under his and Solomon's reigns. In more modern times it is seen as symbol of Jewish unity since Jews consider themselves to be descendants of the very Israelites that David protected with his Shield.
it is for the Jewish religion
The star of David is a factor in Judaism.
Judaism
The Star of David.
The five-sided Star of David
There is no such thing as a "Star" of David. This is a misnomer that originated among non-Jews.Magen David is the Hebrew name for the Shield of David.Magen David means "Shield of David" - and King David's shield was supposedly shaped like the Star of David. The actual origin of the Shield of David is unknown, though it first appeared in the Middle Ages.
It is the Magen David or Star Of David for the nation of Israel. It is the menorah for the religion.
Christianity is a cross, or crucifix. Judaisim is the Star of David. Islam is the moon with the star.
A hexagram is a six-pointed star. It is a combination of two equilateral triangles. It is commonly known as the Star of David or the star that the signifies the Jewish religion.
Wil has, basically, no participation in religion. He got the star of David for his mom.
christian/jewish - hence star of david in annual xmas stars
No religious symbol for Islam religion as the Cross in Christianity or David Star in Judaism.
Our religion does not permit us to wear a cross. No ornament is required, but if a Jew does wear an ornament it will most likely be a six-pointed Star of David.