Exodus 12:21-28

21Then Moses called for all the elders of Israel and said to them, “Go and take a lamb for yourselves according to [the size of] your families and slaughter the Passover lamb.

22You shall take a bunch of hyssop, dip it in the blood which is in the basin, and touch some of the blood to the lintel [above the doorway] and to the two doorposts; and none of you shall go outside the door of his house until morning.

23For the Lord will pass through to strike the Egyptians; and when He sees the blood on the lintel [above the entry way] and on the two doorposts, the Lord will pass over the door and will not allow the destroyer to come into your houses to slay you.

24You shall observe this event [concerning Passover] as an ordinance for you and for your children forever.

25When you enter the land which the Lord will give you, as He has promised, you shall keep and observe this service.

26When your children say to you, ‘What does this service mean to you?’

27you shall say, ‘It is the sacrifice of the Lord’s Passover, for He passed over the houses of the Israelites in Egypt when He struck the Egyptians, but spared our houses.’ ” And the people bowed [their heads] low and worshiped [God].

28Then the Israelites went and did [as they had been told]: just as the Lord had commanded Moses and Aaron, so they did.