21 And the Lord said unto Moses, When thou goest to return into Egypt, see that thou do all those wonders before Pharaoh, which I have put in thine hand: but I will harden his heart, that he shall not let the people go. 22 And thou shalt say unto Pharaoh, Thus saith the Lord, Israel is my son, even my firstborn: 23 And I say unto thee, Let my son go, that he may serve me: and if thou refuse to let him go, behold, I will slay thy son, even thy firstborn.
When Moses fled from Egypt, we were told that Pharaoh, himself, sought to slay him. Since God had assured Moses that everyone who sought his life was now dead, this must have been a new Pharaoh that Moses would contend with. So once again, the Israelite captivity had carried from one generation of rulership to another, still with no end in sight. This new Pharaoh would be given the chance to atone for the sins of his fathers, but the Lord tells Moses that the man will refuse, even in the face of Moses’s miracles. And because of the Pharaoh’s stubbornness, God will exact His vengeance upon the Egyptians, even to the slaying of all their firstborn.
It seems strange that God says, “I will harden his heart, that he shall not let the people go.” Undoubtedly God does have the ability to change the heart of a man, but typically we think of that as being to change the heart for the better, not for the worse. An argument could certainly be made that it feels unjust for God to prevent a man from repenting, and thus requiring him to receive a greater condemnation than he might otherwise have.
Now for me, personally, this passage is not a concern. I am a member of the Church of Jesus Christ of Latter-day Saints, and we believe that this passage is a mistranslation, and that what God said in this, and every other instance, was that Pharaoh would harden his own heart. Obviously, I don’t expect most other Christians to just accept that decision, and obviously there is a slippery slope in declaring certain passages of the Bible as being mistranslated. Before long one might excise any portion of the Bible that teaches something they find personally inconvenient, saying it must simply be a mistranslation. Even so, with serious gravity for the sacredness of the Biblical text, we must accept that it is possible that some parts of it might have been mangled over the years. The oldest, surviving version of the Old Testament is the Septuagint, which was a Greek translation made in the 2nd and 3rd centuries, BC. We no longer have the text that that translation was based off of, let alone the centuries and centuries of copying and translating scriptural text that came before.
If one insists that the text that we have today must be accurate, then there are still a number of commentators who refuse to accept that this passage means that God would harden the heart of a man. Some have suggested God merely means He will not be applying His grace to Pharaoh, and without it, Pharaoh’s heart will naturally remain hardened. Others assert that God really did harden Pharaoh’s heart, but that such a decision is His divine prerogative. I suppose it is up to you to make of this passage what you will.