Exodus 4:23
And I say unto you, Let my son go, that he may serve me: and if you refuse to let him go, behold, I will slay your son, your firstborn.
ā The Restored Word Bible
Context
21 And the Yahuah said unto Moses, When you goest to return into Egypt, see that you do all those wonders before Pharaoh, which I have put in your hand: but I will harden his heart, that he shall not let the people go.
22 And you shall say unto Pharaoh, Thus says the Yahuah, Israel my son, my firstborn:
23 And I say unto you, Let my son go, that he may serve me: and if you refuse to let him go, behold, I will slay your son, your firstborn.
24 And it came to pass by the way in the inn, that the Yahuah met him, and sought to kill him.
25 Then Zipporah took a sharp stone, and cut off the foreskin of her son, and cast at his feet, and said, Surely a bloody husband you to me.