It is a powerful image. If the door is closed, we are on the outside and therefore separated from what is on the inside. If that door leads to life then it becomes imperative that we go through that door. In Christ’s illustration there is no other way in except through that door. It is too strong to be broken down or forced open and there is no point in trying to get in any other way. Entry through the door depends in the willingness of the Lord to open it to us, and all we can do is ask to be let in. There is no pressure we can exert on him to let us in. Only humble pleas will do any good. But once he decides to close the door, he will not open it again; it is closed forever. This inflexibility of the will of the one behind the door is something greatly to be feared (Psalm 2:12).
How will the proud cope with a situation like this? They cannot bully or bluster their way in. They are used to pushing others around in life and getting their own way. They have found deceitful ways of getting around anyone or anything that gets in their way. They have operated in a world that is corrupt like them and they have built up a confidence that nothing can stand in their way for long. They believe that everyone they come across will yield to their corrupting influence. What will happen when they come up against one who is incorruptible, who knows all the deceitfulness of their hearts and who is not won over by any amount of outward show and lies. What will they do when their lives depend on an answer to this situation; when not just life in this world depends on it but eternal life? Although men may leave this world with hearts still hard and bitter against God, on the Day of Judgment every heart will quake and all will cry out for mercy however much they know they do not deserve it.