People do not hear the Lord because they have hardened their hearts. This is a tough nut to crack. They don't hear the Lord knocking at their door. They are blind to any signs from the Lord. They have lost all humility and become completely self-insulated. These people can be Christians too. We have pro-abortion Catholics and Catholics in name only. Jesus said that to enter the kingdom of God, we need to be childlike, just the opposite of having a hardened heart. Sometimes it would take a catastrophe to crack such a hardened heart.