John 12:37 Even after Jesus had performed so many signs in their presence, they still would not believe in him. This was to fulfill the word of Isaiah the prophet: “Lord, who has believed our message and to whom has the arm of the Lord been revealed?” For this reason they could not believe, because, as Isaiah says elsewhere: “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.”
Christ enlightens them by signs, wonders, miracles, and words. These testimonies should shine bright in the darkness so that they/we may believe and follow the way of salvation. For this reason, they who do not choose to look at the light of Jesus Christ and the grace of God extinguish, as far as lies in their power, the light of Jesus Christ which is not only with them but offered to them. One commentator said, “It is perplexing how they came to be so stupid, that the power of God, though visible, produced no effect upon them. Their choice blinded them and in this blindness, their hearts are hardened like stone. We never know what exactly led them o deny Christ. It could have been pride, selfish-ambition, greed, anger, hate, love of this world, lovers of the desires of the flesh, or a host of other reasons. The very same things that have kept millions upon millions from believing in Jesus Christ, the Gospel of Salvation.
Examine your heart. Is it open to the leading of the Holy Spirit or does it take its lead from your fleshly desires? Does it seek and desire to know and be known by Jesus Christ? Does it seek to honor and glorify Him? Does it hunger and thirst for more understanding of His grace, mercy, and love? Do not be blinded by things of this world and what it has to offer. You never know when your heart will become hardened like stone and the light of Jesus Christ will no more be able to enter in.