John 12:40
'He has blinded their eyes and hardened their hearts, so they can neither see with their eyes, nor understand with their hearts, nor turn — and I would heal them' — quoting Isaiah 6:10, John attributes the spiritual blindness to God's action: He has blinded their eyes and hardened their hearts. This presents the difficult theology of divine hardening: God is the agent who prevents perception and understanding, closing the possibility of repentance and healing. This reflects the Johannine tension between human responsibility and divine sovereignty in faith.