Franz Kafka in his famous parable “Before the Law” writes about a man who stands before a door designated only for him, but dies without entering. A very different spirit from Kafka, Ralph Waldo Emerson, nonetheless anticipated the existentialist by writing: “Men live on the brink of mysteries and harmonies into which they never enter, and with their hand on the door latch they die outside.”
During the Neilah service of Yom Kippur, the liturgy tells of the gates closing. The origin is both literal and metaphorical: the gates that closed on the ancient Temple at the end of a long day, and the gates of repentance that are closing in heaven. But the assumption the tradition makes is that we can enter. No one need die outside the gates.
One may see life is a great unfulfillment, where there are promises and possibilities that mock us in our insufficiency. Or we may view life as a series of doors we are able to enter, blessings given and goodness grasped. A mezuzah is hung on the door not as a reminder when you merely see it, but to kiss when you open the door and walk through to the other side.