Exodus 12:22-24

22Take the branch of a hyssop plant, dip it in the blood which is in a bowl, and put some of the blood on the top and sides of the doorframes ⌞of your houses⌟. No one may leave the house until morning.

23The Lord will go throughout Egypt to kill the Egyptians. When he sees the blood on the top and sides of the doorframe, he will pass over that doorway, and he will not let the destroyer come into your home to kill you.

24“You must follow these instructions. They are a permanent law for you and your children.