When considering knowing God the very first thing we say is Jesus. For Jesus is the unveiling of God to us. And as so we say Jesus we also say that God IS Father, Son and Spirit as one communion of love. We say God IS Triune simply because that is the way God has made himself known to us in Jesus within the gospel story. As T. F. Torrance says, “Through his self-revelation in the incarnation God has opened himself to us in such a way that we may know him in the inner relations of his divine Being and have communion with him in his divine life as Father, Son and Holy Spirit”. Trinity isn’t added on to everything else we say about God, Trinity is who he is. So we begin with Jesus and the Triune Communion and continue with this view of God all the way through. Everything else we say about God must be Jesus shaped and thus trinity shaped.
However, when we start speaking about God as Trinity we must be careful to always stick with Jesus. As Geordie Zeigler says reflection on Trinity is not a movement away from Jesus, but a movement further into Jesus. So we don’t attempt to know more of Trinity by leaping into abstract and speculative thinking about the three in one. We stay focussed on Jesus as his Spirit takes us ever deeper into who he is. Then we discover God opening himself to us in such a way that we know him in the inner relations of his divine Being as we share in the Son’s communion with Abba Father by the Holy Spirit”.