Exodus 4:22

And thou shalt say unto Pharaoh, Thus saith the LORD, Israel is my son, even my firstborn:
— Exodus 4:22, King James Version

In other translations

World English Bible (WEB)

You shall tell Pharaoh, 'Thus says Yahweh, Israel is my son, my firstborn,

American Standard Version (ASV)

And thou shalt say unto Pharaoh, Thus saith Jehovah, Israel is my son, my first-born:

Young's Literal Translation (YLT)

and thou hast said unto Pharaoh, Thus said Jehovah, My son, My first-born <FI>is<Fi> Israel,