Gregory of Elvira

Rahab, who is a type of the church, suspended the scarlet thread from her window as a sign of salvation, to show that the nations would be saved through the Lord’s passion.… The house of Rahab and all those with her were saved through the scarlet sign when Jericho was destroyed and burned and its king, a type of the devil, slain. So when this world is destroyed by fire and the devil who now has dominion over the world is overthrown, no one will be preserved for eternal salvation if that one is not found inside the house of the ecclesia which is marked with the scarlet sign, that is, with the blood of Christ. Or again, as in the flood, no one escaped the drowning of the world save those who were preserved in the ark of Noah, which is a type of the church.