John 15:5 - “I am the vine; you are the branches. If a man remains in me and I in him, he will bear much fruit; apart from me you can do nothing.”
Jesus paints us a picture of how our life in Him works. He is the vine, we are the branches. Think about that for a moment in the sense of a grapevine. First the vine; the vine is the main part of the plant. It is attached to the roots. All of the food and water come through the vine to feed the branches. If a branch gets disconnected or broken off the vine it can no longer receive what it needs to live; so it withers and dies.
In order to maintain the plant you trim off the branches that do not bear fruit, or at least the parts of the branch that are not doing anything. That way the food and water will be better dispersed to those parts that are producing good fruit.
Again, this is a picture of how our life is in relation to Jesus. If we become disconnected from Him we will wither and die. Jesus is our source of life and growth. Without Him we have nothing. Apart from Him we know that we can do nothing. We must stay connected to Him in order to grow and flourish.
But what about the trimming part? Think about your life. We all have areas that could use a trimming. There are things that are not producing fruit, but we are still putting a lot of energy into them. Those may need to be trimmed. If you cut those off, or at least “trim” them back you will be able to put more time and energy into those things that bring life.