It is plainly implied in these words that there are two sets of branches in the vine – fruitful and fruitless ones…the professing followers of Christ may be spiritually fruitful, or the reverse…He gives us plainly to understand that as in it (the Church) there would be always some fruit-bearing Christians, because of his dwelling in them by his spirit, so there would also be fruitless ones, because, while externally united to him, they would nevertheless be internally separated from him.
…here is an emblem of the visible Church. It consists of fruitless as well as fruitful branches – of nominal as well as real Christians. And yet the fact that there are fruitless branches in the vine, does not destroy the connection between Christ and his true people.
This is exactly what Ridderbos writes in his commentary, the words in which being extremely important, especially when coupled with dividing...
‘What makes Jesus the true vine is that, as the one sent by God, he gathers a community, a fellowship of life, in which his word exerts a redeeming, life-creating, continually purifying, and dividing effect.’
‘There is a sort of fellowship with Jesus, a temporary faith and fruitbearing…’
Here we have the only, for me at least, satisfactory explanation of the Vine imagery which Jesus employs in John 15. The Vine represents Jesus, the true embodiment of the covenant people of God in the new covenant. All who belong to the covenant community are in some sense joined to Christ. Some within the covenant community will reject the covenant and be lost. It is only within the biblical category of covenant that the Johannine warnings of falling away make sense alongside the doctrine of election. Jesus is the True Vine, the True Israel, and the Church is his body. Thanks be to God.