In Galatians 5, the apostle Paul gives a list of characteristics of those who belong to God. These attributes are identified as the "fruit of the Spirit." We get the background of what he's talking about in John 15. Jesus describes Himself as the True Vine. Just as grapes grow on vines from the branches, if you remove the branch from the vine; the branch, along with the grapes will die. Paul imagines us as men and women who are firmly engrafted on to the Holy Spirit as our "vine". It is only as He is providing us with the nourishment we need to grow that we are able to produce the fruit we were intended to bear. It is only as we remain attached to the "Holy Spirit" vine that we can bear "spiritual" fruit.