Doors are meant to do two things: to open and provide access, and to close and prevent it. Jesus addresses the Church at Philadelphia as the One who has the Key of David and can open and shut. He is the only one who can provide access. He is the key to the door to heaven. Through Him we have access to the perfect joys of heaven itself. He is the Way, He is the Key, He is the Door. There’s another side to this. Unbelief and unforgiven sin put up a barrier that prevents us from coming to God’s presence. Those who persist in this cannot enter heaven. Sin prevents us from entry into God’s eternal blessings. Yet this free gift is available for everyone. Faith, not works, opens the door.