Exodus 4:22-24

King James Version

²² And thou shalt say unto Pharaoh, Thus saith the Lord, Israel is my son, even my firstborn:

²³ 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.

²⁴ And it came to pass by the way in the inn, that the Lord met him, and sought to kill him.