Notice the door. Jesus is standing before a door partially covered with creeping ivy. Notice the hinges. The door's iron hardware and nails are rusty, suggesting that this door has not been opened in some time. What Hunt portrays so successfully is "Listen! I am standing at the door, knocking; if you hear my voice and open the door, I will come in to you and eat with you, and you with me."
What Holman Hunt's portrait of a door-knocking Jesus reminds us of is that the message and mission of Jesus Christ is not accomplished solely through interior introspection. Faith is not an inward-directed, contemplative life. Faith is action. Faith goes outdoors to live and play, to love and work.
While it may appear that Jesus is knocking on the door of the human heart to get in, Jesus is actually knocking on our door to invite us out -- out to be a part of God's mission in the world.
Perhaps we do well to realize that as Jesus is portrayed in Hunt's famous picture, there is no handle on the outside of the door. The point is that it is clearly up to each individual as to whether or not we will take the initiative to open the door from within to Christ. Only then, will he meet us face to face -- and in the process equip us to do the same toward others. This, indeed, is Jesus knocking on the door of life to invite us out to become a part of God's mission in the world.