Exodus 12:7, 11-12

Moreover, they shall take some of the blood and put it on the two doorposts and on the lintel [above the door] of the houses in which they eat it. [Matt 26:28; John 1:29; Heb 9:14]

Now you are to eat it in this manner: [be prepared for a journey] with your loins girded [that is, with the outer garment tucked into the band], your sandals on your feet, and your staff in your hand; you shall eat it quickly—it is the LORD’S Passover. For I [the LORD] will pass through the land of Egypt on this night, and will strike down all the firstborn in the land of Egypt, both man and animal; against all the gods of Egypt I will execute judgments [exhibiting their worthlessness]. I am the LORD.