Exodus 12:22-23

New International Version

²² Take a bunch of hyssop,^(A) dip it into the blood in the basin and put some of the blood^(B) on the top and on both sides of the doorframe. None of you shall go out of the door of your house until morning. ²³ When the Lord goes through the land to strike^(C) down the Egyptians, he will see the blood^(D) on the top and sides of the doorframe and will pass over^(E) that doorway, and he will not permit the destroyer^(F) to enter your houses and strike you down.