How does Star of David relate to religion?

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