We cannot do anything without God, He is the sustainer of our lives according the Scripture you quoted in John 15. Many believers in the church today are spritually dead because they have disconnected from their source and where they receive nourishment, the same cannot happen to us, we should abide in God as we love one another, stay prayerful, studying the word and doing the will of God. I really love the message at John 15, thanks for sharing with us