Exodus 12:23-25

New International Version - UK

²³ When the Lord goes through the land to strike down the Egyptians, he will see the blood on the top and sides of the door-frame and will pass over that doorway, and he will not permit the destroyer to enter your houses and strike you down.

²⁴ ‘Obey these instructions as a lasting ordinance for you and your descendants. ²⁵ When you enter the land that the Lord will give you as he promised, observe this ceremony.