'Blood is thicker than water' indicates that ties to the family come before any other alliances. Yet the 'blood' could also refer to the sealing of a covenant.
On the Day of Atonement, the one goat's blood cleansed the altar of all the sins, while the azazel took them away. Jesus Christ fulfilled both these roles.
Hebrews 11 provides examples to bolster faith. The faith described is not blind, but is carefully developed from systematic analysis of available evidence.