Exodus 12:3, 6-7, 12-13

Speak to all the congregation of Israel, saying: ‘On the tenth of this month every man shall take for himself a lamb, according to the house of his father, a lamb for a household.

Now you shall keep it until the fourteenth day of the same month. Then the whole assembly of the congregation of Israel shall kill it at twilight. 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.

‘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.