Exodus 12:29-30
"And it came to pass, that at midnight the LORD smote all the firstborn in the land of Egypt, from the firstborn of Pharaoh that sat on his throne unto the firstborn of the captive that was in the dungeon; and all the firstborn of cattle. And it came to pass, that at midnight the LORD smote all the firstborn in the land of Egypt, from the firstborn of Pharaoh that sat on his throne unto the firstborn of the captive that was in the dungeon; and all the firstborn of cattle."



Exodus 11:5
"All the firstborn sons will die in every family in Egypt, from the oldest son of Pharaoh, who sits on his throne, to the oldest son of his lowliest servant girl who grinds the flour. Even the firstborn of all the livestock will die."


Romans 9:15-16 "For he saith to Moses, I will have mercy on whom I will have mercy, and I will have compassion on whom I will have compassion. So then it is not of him that willeth, nor of him that runneth, but of God that sheweth mercy."