The origins of the Passover festival predate the Exodus.[16] The Passover ritual, prior to Deuteronomy, is widely thought to have its origins in an apotropaic rite, unrelated to the Exodus, to ensure the protection of a family home, a rite conducted wholly within a clan. Hyssop was employed to daub the blood of a slaughtered sheep on the lintels and door posts to ensure that demonic forces could not enter the home.[17]