Whoever wrote the gospel according to Mark invented the genre "gospel book." It was an innovation, probably made about 70 CE, sometime after the death of Paul and probably about 40 years after the crucifixion of Jesus, that had stunning results. Three other gospels soon followed, each making significant use of Mark. But neither Mark nor the others disappeared. We still have all four.
Mark remains quite alive, characterized by its own unique voice and full of surprises. For one thing, unlike the other gospels, the book includes its own title: "The beginning of the gospel of Jesus Christ, the Son of God . . ." This has sometimes been taken simply as an introduction to the next few lines about John the Baptist. It should, rather, be regarded as the name for what the whole book is and what it enables. Mark provides the beginning or the ground or basic principle of the gospel as it is to be proclaimed and celebrated in the assemblies--the churches--of the Christians. Indeed, in Mark, the good news, or the gospel, involves not only words about Jesus, but his risen presence in those words and in those assemblies.
The ending of Mark sends those who are reading the book back to Galilee to see him alive, as both the young man in the tomb and Jesus himself have told us. And "Galilee" happens when we start to read the book. It also happens in the very center of the book, the central one of the three passion predictions where an assembly in a house in Galilee is told "whoever welcomes one such child in my name welcomes me, and whoever welcomes me welcomes not me but the one who sent me." To be in assembly, to hear the words about Jesus, his ministry, and his death, and to welcome the least ones--such is to see the Risen One. And that one, Jesus Christ, is the very presence of God.
Mark is not a simple book. Or its seeming simplicity invites us always to come deeper. From its beginning, the book involves the revealing of a secret, the manifestation of the presence of God in the world like seed growing secretly, like deeds of power breaking out even when people do not believe, like yes when no has been spoken. Every passage needs to be thought about. So not only are the heavens town open, but so is the temple curtain, and God comes graciously to be present where we thought God could not be: on the earth, on the cross. An annual mustard bush becomes the tree that gives shelter to all--that is, Christ's cross is the promised tree of life. A blind man named after a figure in the writings of Plato comes to see because Jesus goes past him on the way to the Cross. Jesus drinks the sour wine and he is inaugurating the presence of the kingdom. And a place in the life-giving tree and healing from our blindness and a drink from the cup of the kingdom then comes to us. In the crucified and risen Christ, God comes to us.
I love the gospel of Mark because of its paradoxical simplicity, because of its secret made manifest in the assembly, because the whole book is a resurrection appearance of Jesus. I love Mark because it so faithfully and fascinatingly enacts the beginning of the gospel among us.
From "Why Mark is My Favorite Gospel" by Gordon Lathrop