Exodus 12:23-25

The Voice

²³ The Eternal will pass through the land during the night and bring death to the Egyptians. But when He sees the blood-markings across the tops of your doorways and down your two doorposts, He will pass over your houses and not allow His messenger of death to enter into your houses and strike you down. ²⁴ You and all your descendants are obligated to keep these instructions for all time. ²⁵ Even after you arrive in the land the Eternal has promised you—the land flowing with milk and honey—you must keep these instructions and perform this ritual.