The eight-pointed star is the Star of Redemption or Regeneration and represents baptism. Eight is traditionally the number of regeneration, and thus many baptismal fonts have an octagonal base.
Providing added significance is the assumption that Jesus was circumcised and named when he was eight days old (the traditional Jewish practice); baptism is seen as the New Testament equivalent of circumcision.
Finally, eight persons were saved in Noah's ark, which is another Old Testament parallel of baptism.
Related Bible Verses
For we ourselves were also once foolish, disobedient, deceived, serving various lusts and pleasures, living in malice and envy, hateful and hating one another. But when the kindness and the love of God our Savior toward man appeared, not by works of righteousness which we have done, but according to His mercy He saved us, through the washing of regeneration and renewing of the Holy Spirit, whom He poured out on us abundantly through Jesus Christ our Savior, that having been justified by His grace we should become heirs according to the hope of eternal life. (Titus 3:3-6, NKJV).
When his son Isaac was eight days old, Abraham circumcised him, as God commanded him. (Genesis 21:4, NIV).
...they formerly did not obey, when God's patience waited in the days of Noah while the ark was being prepared, in which a few, that is, eight persons, were brought safely through water. Baptism, which corresponds to this, now saves you, not as a removal of dirt from the body but as an appeal to God for a good conscience, through the resurrection of Jesus Christ, who has gone into heaven and is at the right hand of God. (1 Peter 3:18-22, ESV).