Exodus 4:22–23

Then you shall say to Pharaoh, ‘Thus says the Lord, Israel is my firstborn son, and I say to you, “Let my son go that he may serve me.” If you refuse to let him go, behold, I will kill your firstborn son.’ ”

Then say to Pharaoh, ‘This is what the Lord says: Israel is my firstborn son, and I told you, “Let my son go, so he may worship me.” But you refused to let him go; so I will kill your firstborn son.’ ”

Then you will tell him, ‘This is what the Lord says: Israel is my firstborn son. I commanded you, “Let my son go, so he can worship me.” But since you have refused, I will now kill your firstborn son!’ ”

And you must say to Pharaoh, ‘Thus says Yahweh, “Israel is my son, my firstborn.” And I said to you, “Release my son and let him serve me,” but you refused to release him. Look, I am about to kill your son, your firstborn.’ ”

And thou shalt say unto Pharaoh, Thus saith the Lord, Israel is my son, even my firstborn: And I say unto thee, Let my son go, that he may serve me: and if thou refuse to let him go, behold, I will slay thy son, even thy firstborn.