When a star is used as a symbol in the Christian faith, the number of points it has is especially significant because it adds meaning to the sign.
In this case, the number 12 has special symbolic meaning in the Bible, often depicting completeness.
Both the Old and New Testaments find special meaning in the number 12. In the Old Testament, 12 often represents God's people because Israel was comprised of 12 tribes. In the New Testament, 12 may represent the church, which was built upon the life and ministry of the 12 apostles.
The 12-point star may also be used at Epiphany, the twelfth day of Christmas, on which the church celebrates the manifestation of Christ as the Son of God.
Reference
- "Symbols in Christian Art" by Walter E. Gast.