Christian commentators have offered several closely related explanations. Many emphasize that Pharaoh was already proud, oppressive, and determined to resist God. The biblical narrative repeatedly describes him hardening his own heart before later emphasizing God's role in hardening it.
Under this understanding, God confirmed Pharaoh in the rebellious course he had freely chosen. Rather than forcing an innocent ruler to become wicked, God permitted Pharaoh's existing resistance to become increasingly entrenched.
Other Christian theologians emphasize God's sovereignty over history. They understand the hardening as part of God's deliberate judgment, through which His power would be revealed and Israel would be delivered. They nevertheless maintain that Pharaoh remained responsible for his wicked decisions.
Both approaches recognize the tension between divine sovereignty and human responsibility. Scripture presents Pharaoh as genuinely rebellious while also declaring that God was accomplishing His purposes through the confrontation.