Any honest reader of John’s Gospel would be asking the question, “Why don’t these people believe in Jesus after seeing all these miracles?” John answers this question.
Their unbelief is a fulfillment of prophecy
The people did not understand that the Messiah would die to deliver His people. In Isaiah 53, Isaiah prophesied that that is exactly what the Messiah would do; however, he begins that prophecy by stating that no one would believe his report. Through the inspiration of the Holy Spirit, Isaiah was right on both accounts. Jesus died for His people, and no one believed it.
God has hardened their hearts
Why didn’t they believe? God had closed their eyes and hardened their hearts so that they could not believe. This is exactly what happened to Pharaoh and the people of Isaiah’s day. God hardened their hearts so that they could not repent. This idea is very hard for us to accept.
We have a wrong view of God
This idea of God hardening men’s hearts does not set well with us because we have a wrong view of God. We view God as a dog laying at our feet waiting for our command. We can ignore Him and sin against Him for most of our lives, but when we need Him He will be right there. This simply is not the case. God is not a puppet on our string. We are a puppet on His. He is sovereign, not us. He is the Potter; we are the clay.
God noes no violence to man’s will
The idea of hardening does not mean that God drags people against their will. Hardening is simply setting something the way that it already is. God is simply giving them what they asked for. Pharaoh was a God-hating idolater long before God hardened his heart. God just gave Pharaoh over to his sin. The same is true of the Jews and Greeks in John 12. They did not want to see their sin, so God made them blind. They did not want to hear what God had to say, so God made them deaf. They did not want to feel conviction, so God hardened their hearts.
The same is true today. If you close your eyes long enough God will make you blind. If you keep running from the Lord He will let you go. If you are sick and tired of feeling guilt, conviction, and shame when you sin God will just harden your heart so you no longer feel. Be careful what you wish for; God may give it to you.
There are two responses to this teaching. One response is to see that others are blind and need of repentance; this is evidence of someone whose heart is already hard. The other is to see that oneself is blind and cry out to God for sight (John 9:39-41.) Which one are you?