Why did God harden Pharaoh's heart?  by Got Questions

Exodus 7:3-4 says, “But I will harden Pharaoh’s heart, and though I multiply my miraculous signs and wonders in Egypt, he will not listen to you. Then I will lay my hand on Egypt and with mighty acts of judgment I will bring out...my people the Israelites.” It seems unjust for God to harden Pharaoh’s heart and then to punish Pharaoh and Egypt for what Pharaoh decided when his heart was hardened. Why would God harden Pharaoh’s heart just so He could judge Egypt more severely with additional plagues?

First, Pharaoh was not an innocent or godly man. He was a brutal dictator overseeing the terrible abuse and oppression of the Israelites, who likely numbered over 1.5 million people at that time. The Egyptian pharaohs had enslaved the Israelites for 400 years. A previous pharaoh—possibly even the pharaoh in question—ordered that male Israelite babies be killed at birth (Exodus 1:16). The pharaoh God hardened was an evil man, and the nation he ruled agreed with, or at least did not oppose, his evil actions.

Second, on least a couple occasions, Pharaoh hardened his own heart against letting the Israelites go: “But when Pharaoh saw that there was relief, he hardened his heart” (Exodus 8:15). “But this time also Pharaoh hardened his heart” (Exodus 8:32). It seems that God and Pharaoh were both active in one way or another in the hardening of Pharaoh’s heart. As the plagues continued, God gave Pharaoh increasingly severe warnings of the final judgment to come. Pharaoh chose to bring further judgment on himself and his nation by hardening his own heart against God’s commands.

It could be that, as a result of Pharaoh’s hard-heartedness, God hardened Pharaoh’s heart even further, allowing for the last few plagues and bringing God’s full glory into view (Exodus 9:12; 10:20, 27). Pharaoh and Egypt had brought these judgments on themselves with 400 years of slavery and mass murder. Since the wages of sin is death (Romans 6:23), and Pharaoh and Egypt had horribly sinned against God, it would have been just if God had completely annihilated Egypt. Therefore, God’s hardening Pharaoh’s heart was not unjust, and His bringing additional plagues against Egypt was not unjust. The plagues, as terrible as they were, actually demonstrate God’s mercy in not completely destroying Egypt, which would have been a perfectly just penalty.