Jesus explains to us today a great deal through this metaphor of the vine and the branches. He tells us that he is vine, which is to say that he is the center, the foundation of reality. There are branches on this vine. We are the branches. We are peripheral and contingent.
Some branches do not bear fruit, so they are removed. These branches have failed at their purpose in life. There is a long standing debate between philosophers who believe that life has a purpose and philosophers who believe that we make our own purpose up as we go along. Jesus falls on one clear side of this debate. Every branch has a purpose: to bear fruit. It is not up to the branch to decide what it is going to do with its life. Every life has a purpose: to bear fruit. To be good means to bear fruit, to fulfill your purpose. To be bad means to be fruitless, to waste your life.
What is fruit? Fruit is the part of a plant that is not meant for itself. It is meant for others. A branch that does not bear fruit is completely self-concerned. It may be a strong, healthy branch, but it has never lived for others. What is fruit? Fruit is the part of the plant responsible for reproduction. A branch that does not bear fruit is doing nothing to prepare the seed of faith which they received for others.
But if a branch is bearing fruit, Jesus says, it must be pruned, which is to say, cut back. It is not enough to bear just any fruit. Jesus wants us to bear good fruit, so he cuts back what is going astray and allows what is promising to come to maturity. He prunes us with his word, his teachings which tell us what parts of our lives we need to cut off and what we need to encourage.
Jesus also tells us what would be a supremely arrogant phrase unless he is God himself: “Without me you can do nothing.” We branches exist to remain with the vine. A branch that has broken off the vine is not even a branch anymore; it is just a stick. Even if we were producing wonderful fruit, but then broke off from the vine, it will never mature. All of our nourishment, all of our life, comes from the vine.