EXODUS 12

12 On that night I will go through all the country of Egypt, and I will kill all the oldest males in Egypt, both humans and animals. By doing this I will show that all the gods in Egypt are worthless. I can do this, because I am Yahweh, the all-powerful God. 13 The blood that you smear on the doorways will be a mark to indicate the houses in which you Israelis live. When I see the blood, I will ignore and pass by those houses, and I will not harm you Israelis who live there, when I punish the Egyptians.