Exodus 10:27

Ἐσκλήρυνεν δὲ Κύριος τὴν καρδίαν Φαραώ, καὶ οὐκ ἐβουλήθη ἐξαποστεῖλαι αὐτούς.

But the LORD hardened the heart of Pharao, and he was not willing to send them away.

ויחזק יהוה את־לב פרעה ולא אבה לשׁלחם׃