Doesn’t God Want Repentance?
Why did God tell Isaiah to make the heart of the people dull, and their ears heavy, and their eyes blinded so that they wouldn't repent? Doesn't God want all people to come to repentance? It seems like God prevented the Israelites in Isaiah's day and in Jesus's from hearing, seeing, and understanding, and thus from repenting.
Your first questions references Isaiah 6:9-10 (NIV)
He said, “Go and tell these people:
“‘Listen continually, but don’t understand. Look continually, but don’t perceive.’ Make the hearts of these people calloused; make their ears deaf and their eyes blind. Otherwise they might see with their eyes and hear with their ears, their hearts might understand and they might repent and be healed.”
This passage is a prophecy that has a “near” fulfillment and a “far” fulfillment. Isaiah 5 portrays God as the owner of the vineyard (Israel) which has failed to produce fruit. Israel has turned away from its covenant with God, and their hearts are already calloused. Israel is unfaithful, and God has pronounced judgment.
In this context, as Isaiah preaches repentance, the people will listen, but not understand. As they continue to reject God by rejecting his word, their hearts will become harder and harder. Isaiah can actually “make their ears deaf and their eyes blind” by preaching repentance. At the same time, God does not want them to repent, because he has already pronounced judgment (Isa. 5:5).
Isaiah 6:9-10 is quoted six times in the New Testament (Matt. 13:13-15; Mark 4:12; Luke 8:10; John 12:40; Acts 28:25-28; Rom. 11:8).
Matt 13:13-15 (NIV)
For this reason I speak to them in parables: Although they see they do not see, and although they hear they do not hear nor do they understand. And concerning them the prophecy of Isaiah is fulfilled that says:
‘You will listen carefully yet will never understand, you will look closely yet will never comprehend. For the heart of this people has become dull; they are hard of hearing, and they have shut their eyes, so that they would not see with their eyes and hear with their ears and understand with their hearts and turn, and I would heal them.’
Jesus spoke in parables to reveal truth to his disciples, hide truth from unbelievers, and to fulfill Isaiah 6:9-10. Much like the Israelites had rejected God, many people were seeing Jesus’ ministry of exorcisms and healings, but not perceiving what that meant. They were hearing Jesus’ message of the kingdom of God, but never understanding the presence of the kingdom in Jesus’ ministry. When people attribute what Jesus says and does to demonic authority or to Jesus’ (allegedly disturbed) state of mind, they do not perceive or understand God’s presence in his preaching and healings, which results in divine judgment. Part of that judgment is having the truth hidden from them.
In both the ministry of Isaiah and Jesus, those who had already rejected God had the truth hidden from them.
Doesn't God want all people to come to repentance?
Yes and no. It is God’s moral will that all would come to repentance. But it his effective will (what God actually brings about) that only some will come to repentance. In the ministries of Isaiah and Jesus, those who rejected God were kept from an understanding that would lead to repentance. This was judgment for having rejected God.
How God’s desire for all to repent and God’s effective Gospel call to some intersect with man’s free will is something that we will never be able to understand.