Exodus 12:12-14

12 "I will pass through the land of Egypt on that night and strike every firstborn [male] in the land of Egypt, both man and beast. I am the Lord; I will execute judgments against all the gods of Egypt.
13 The blood on the houses where you are staying will be a distinguishing mark for you; when I see the blood, I will pass over you. No plague will be among you to destroy [you] when I strike the land of Egypt.
14 "This day is to be a memorial for you, and you must celebrate it as a festival to the Lord. You are to celebrate it throughout your generations as a permanent statute.
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