Exodus: Chapter 12,Verse 7: And they shall take some of the blood and put it on the two doorposts and on the lintel of the houses where they eat it.
Verse 11: And thus you shall eat it: with a belt on your waist, your sandals on your feet, and your staff in your hand. So you shall eat it in haste. It is the LORD Passover.

Verse 12-13: ‘For I will pass through the land of Egypt on that night, and will strike all the firstborn in the land of Egypt, both man and beast; and against all the gods of Egypt I will execute judgment: I am the LORD. Now the blood shall be a sign for you on the houses where you are. And when I see the blood, I will pass over you; and the plague shall not be on you to destroy you when I strike the land of Egypt.