“Every branch in Me that does not bear fruit He takes away, and every branch that does bear fruit He prunes, that it may bear more fruit. Already you are clean because of the word that I have spoken to you. Abide in me, and I in you. As the branch cannot bear fruit by itself, unless it abides in the vine, neither can you, unless you abide in me. I am the vine; you are the branches. Whoever abides in me and I in him, he it is that bears much fruit, for apart from me you can do nothing. If anyone does not abide in me he is thrown away like a branch and withers; and the branches are gathered, thrown into the fire, and burned.” (John 15:2–6, ESV)
In verse 1 Jesus had said that He was the vine and His Father was the vinedresser. In verse 2 He adds to the picture that branches attached to the vine. In doing this He points to two different types of branches. The first group are those that do not bear fruit. These are the ones that do not have the life of the vine in them and consequently they remain dead despite any claims that they might make to the contrary. These are the ones that prove by their lack of fruit that they never really were a part of the vine. They never were in Christ who is that vine and they never garnered the nurturing attention of the vinedresser. In simple terms they never were saved and they never had a place, and their lack of fruit will be the proof, and the ultimate end is that they will be pruned and cast away.
The second group, however, represents those who have believed in Christ and are saved. These are the ones who place in Him (in the vine) is eternally secure and they will bear fruit. Their fruit-bearing is the outflow of who they are and who they belong to. The Spirit of God in them enlivens them and they will bear fruit.
Having fruit trees in my backyard is a constant reminder that they need attention. Abundant fruit does not happen automatically. It happens as a result of being tended to properly at all stages. It requires pruning out the suckers which take nutrients and energy away from the fruit bearing branches, and these branches require the constant flow of nourishment coming up through the trunk. In the believer this means that God takes away those things that get in the way, those things that are not reflective of who we are to be in Christ, and those things that hinder our growth. Anything that drains from our spiritual life is a branch that needs to be pruned. But the one thing we can be assured of is that there is a big difference between being a branch that is cut off and thrown away and a branch that is properly pruned so that it might bear more fruit. Both are uncomfortable, but one is permanent and the other brings growth.
Jesus continued to explain in the verses that followed just what this meant. He assured His disciples in verse 3 that they would remain just as He had already told them that they were clean. Sure they would have some pruning, but in their pruning they would continue to grow, flourish, and bear more and more fruit. The end of the rest that do not believe is that they are cut off and thrown into the heap to be burned with all of the rest. Looking to the end of the story as revealed in Revelation this truly is what will happen to them. Both groups of branches are real people making real choices. One choose to believe in the Son and are saved. The other refuse to believe and are cut off. God is not content letting dead branches slide into His presence, nor is He content letting live ones go unpruned. Some might find the pruning more difficult than others. As believers we are called not to live as if we are apart from the vine, as if we had our own source of nutrients, but as ones who constantly abide in Christ. In the verses that follow Jesus will talk more about the benefits of abiding in Him.