NOTES for Joh 15:1-8
We are called to abide in the vine because, when separated from it, the branches are cut off from the source of life and quickly wither. The branches are free to break away, but they themselves will gain nothing from it. None of the branches grafted into this vine can remain fruitless. The Gardener calls us to bear fruit precisely because He constantly prunes the branches and enables them to do so—each branch according to its own measure, and there is no need to be troubled that each has a different measure. But if we refuse to bear fruit and intend to settle comfortably on the vine without making any effort, we will fall away from it. We are warned that in that case we will be cast out and wither. In fact, we will begin withering even before visibly separating from the vine, for a branch that has not completely broken off but is separating inwardly already deprives itself of life-giving sap.
It is no accident that fallen vine branches are used as a symbol of spiritual barrenness. Once cut off, their weakness when dry makes them unsuitable for use in objects such as baskets or fences. Even as fuel they are inferior to other branches: they burn quickly and give little heat...