The sermon today was about John 12:27-50, which deals with the unbelief of the people. Something that stuck out to me was the quotation from Isaiah that is included in the passage:
"He has blinded their eyes and hardened their heart, lest they see with their eyes, and understand with their heart, and turn, and I would heal them."
It is one of many places in the Bible that talks about how God "hardens the heart" of someone as part of His plan of redemption. God hardens the heart of Pharaoh in Exodus as part of the plan to rescue Israel and move them to the Promised Land, and here God is hardening the collective heart of (most of) the Jewish people, it seems in order to make sure that Jesus gets crucified.
This makes it seem like God is kind of cruel to decide at a certain point in the person's life (or the nation's life in this case) to make it impossible for that person or people to ever believe and thereby be saved.
But as it turns out, all God is doing is solidifying what is just waiting in their hearts to be solidified.
Imagine two cups filled with what appears to identical amounts of white mineral powder. You pour some water into both cups and stir it up. When they are both dry, one is as hard as rock, one stays soft. What's the difference? One was plaster, one was talc! The plaster is made of crystals, that bond together in the presence of water - the talc does not.
It is in the nature of plaster to harden; it is in the nature of talc not to. We can use the plaster to accomplish a task we have in mind; make a smooth wall, for example. That does not mean we are being cruel to the plaster - we're just choosing a time to harden the plaster.