So I say to you, let My son go that he may serve Me. But if you refuse to let him go, indeed I will kill your son, your firstborn.""'
Exodus 4:23
Surrounding context
4:22 Then you shall say to Pharaoh, "Thus says the LORD: "Israel is My son, My firstborn.
4:23 So I say to you, let My son go that he may serve Me. But if you refuse to let him go, indeed I will kill your son, your firstborn.""'
4:24 And it came to pass on the way, at the encampment, that the LORD met him and sought to kill him.