Philip asked Jesus to show them the Father.  Jesus replied, “Anyone who has seen me has seen the Father. How can you say, ‘Show us the Father’?  Don’t you believe that I am in the Father and that the Father is in me? The words I say to you I do not speak on my own authority. Rather, it is the Father, living in me, who is doing his work.  Believe me when I say that I am in the Father and the Father is in me (John 14:8-11).

Here, Jesus tells us that God is One as a communion of three persons mutually indwelling one another.  In saying this, Jesus has taken us into depths that leave us beyond our depth.  And maybe that’s where we should be when discussing this unique oneness.  Only God’s Spirit can help us to know in a way that takes us beyond our own knowing.  He is the Spirit of truth who guides us into all truth.  He takes the things of Christ and makes them known to us.  But the Spirit doesn’t simply show us the mutual indwelling of three persons. The Spirit unites us with Jesus to share in his communion with the Father in the Spirit.  And from within this communion, we glimpse the unique oneness of Father, Son and Spirit mutually indwelling one another in self-giving love. We do not gain mastery over the Oneness of God so we have got it sorted. We rather find ourselves gazing into the Mystery of God as three persons in one communion of love.