Exodus 12:28

24 And you are to keep this command as a permanent statute for you and your descendants.

25 When you enter the land that the LORD will give you as He promised, you are to keep this service.

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

27 you are to reply, ‘It is the Passover sacrifice to the LORD, who passed over the houses of the Israelites in Egypt when He struck down the Egyptians and spared our homes.’” Then the people bowed down and worshiped.

28 And the Israelites went and did just what the LORD had commanded Moses and Aaron.

29 Now at midnight the LORD struck down every firstborn male in the land of Egypt, from the firstborn of Pharaoh, who sat on his throne, to the firstborn of the prisoner in the dungeon, as well as all the firstborn among the livestock.

30 During the night Pharaoh got up—he and all his officials and all the Egyptians—and there was loud wailing in Egypt; for there was no house without someone dead.

31 Then Pharaoh summoned Moses and Aaron by night and said, “Get up, leave my people, both you and the Israelites! Go, worship the LORD as you have requested.

32 Take your flocks and herds as well, just as you have said, and depart! And bless me also.”

Read all of Exodus 12