Today’s Gospel has a very mystical tone to it. The reality that Christ is describing — the oneness of the Christian with Christ, the Christian living in Christ — is a mystical reality, which we can neither fully describe nor explain. Christ has revealed to us the fact of our mystical oneness with him. And with this metaphor, he tries to give us some insights into what that oneness involves.
In a wondrous manner, while maintaining his individuality and his personal identity, the Christian remains one with Christ, as the branch is one with the vine; the Christian lives in Christ, has his being in Christ, as the branch lives and has its being in the vine. When the branch produces fruit, it is the vine that is fruitful. So also when the Christian acts, by some mysterious alchemy of divine Providence, it is, in reality, Christ who is acting. And as the branch cannot bear fruit if it is not in the vine, the Christian can bear no fruit unless he is in Christ.
But these are all merely empty words. We should not approach a reality of the life of the Christian in Christ, by way of intellect and reason. We are reminded to go to prayer in the hope that doing so, God will give us the grace to intuitively comprehend this mystery.