Exodus 12:7, 11-12

Moreover, they shall take some of the blood and put it on the two doorposts and on the lintel of the houses in which they eat it.

Now you shall eat it in this manner: with your loins girded, your sandals on your feet, and your staff in your hand; and you shall eat it in haste—it is the LORD’S Passover. For I will go through the land of Egypt on that night, and will strike down all the firstborn in the land of Egypt, both man and beast; and against all the gods of Egypt I will execute judgments—I am the LORD.