(Rom 9:17-18) For the Scripture says to Pharaoh: “I raised you up for this very purpose, that I might display my power in you and that my name might be proclaimed in all the earth.” 18 Therefore God has mercy on whom he wants to have mercy, and he hardens whom he wants to harden.
Paul is quoting from —
(Exo 9:16-17) But I have raised you up for this very purpose, that I might show you my power and that my name might be proclaimed in all the earth. 17 You still set yourself against my people and will not let them go.
Notice, first, God’s purpose: to show the world who is God. Pharaoh claimed to be a god. Egypt was the most powerful nation in the world (or that part of the world). God wanted to make a point.
But let’s look at how God went about doing it.
(Exo 7:2-5) You are to say everything I command you, and your brother Aaron is to tell Pharaoh to let the Israelites go out of his country. 3 But I will harden Pharaoh’s heart, and though I multiply my miraculous signs and wonders in Egypt, 4 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 divisions, my people the Israelites. 5 And the Egyptians will know that I am the LORD when I stretch out my hand against Egypt and bring the Israelites out of it.”
First, it’s indisputable that God takes credit for hardening Pharaoh’s heart. But he has a purpose: to prove that he is the one true God. He is not refusing to allow someone to come to faith. He is not choosing who goes to heaven. Rather, he is encouraging a pagan despot to act like a pagan despot.
Moreover, the scriptures are clear that, although God sometimes did the hardening, other times, Pharaoh hardened his own heart.
(Exo 7:22-23) But the Egyptian magicians did the same things by their secret arts, and Pharaoh’s heart became hard; he would not listen to Moses and Aaron, just as the LORD had said. 23 Instead, he turned and went into his palace, and did not take even this to heart.
(Exo 8:15) But when Pharaoh saw that there was relief, he hardened his heart and would not listen to Moses and Aaron, just as the LORD had said.
(Exo 8:32) But this time also Pharaoh hardened his heart and would not let the people go.
(Exo 9:34) When Pharaoh saw that the rain and hail and thunder had stopped, he sinned again: He and his officials hardened their hearts.
Here’s the point. If God had not hardened Pharaoh’s heart, he still would not have been among the elect. God did not harden his heart so that he could not be God’s elect. He hardened an already very hard heart — a heart that Pharaoh himself hardened as well — so that the full might of God could be shown.
This passage has nothing to do with someone being denied election or salvation by God’s hardening. Rather, it’s God making an evil Pharaoh show the full measure of his iniquity so that other nations would be afraid and leave Israel alone — and so Egypt would not march on the wandering Israelites later while they were defenseless in the desert.
This is very much in line in with Paul’s teaching in chapter 1, as is —
(Rom 9:18) Therefore God has mercy on whom he wants to have mercy, and he hardens whom he wants to harden.
Yes, but he wants to have mercy on those with faith and to harden those without faith. This is, in fact, an allusion to chapter 1.