Exodus 10:27

But the LORD hardened Pharaoh’s heart, and he would not let them go.
— Exodus 10:27, King James Version

In other translations

World English Bible (WEB)

But Yahweh hardened Pharaoh's heart, and he wouldn't let them go.

American Standard Version (ASV)

But Jehovah hardened Pharaoh’s heart, and he would not let them go.

Young's Literal Translation (YLT)

And Jehovah strengtheneth the heart of Pharaoh, and he hath not been willing to send them away;