Parallel
Exodus 10:20
Rahlfs Septuagint (1935) · Berean Standard Bible
καὶ ἐσκλήρυνεν κύριος τὴν καρδίαν Φαραω καὶ οὐκ ἐξαπέστειλεν τοὺς υἱοὺς Ισραηλ
But the LORD hardened (note: Or stiffened or strengthened; also in verse 27) Pharaoh’s heart, and he would not let the Israelites go.