I recently heard a meditation on Rublev’s icon of the Trinity, called The Hospitality of Abraham. The icon, based on the story of Genesis 18:1-15, depicts Abraham’s three visitors, who within the icon represent the Father, Son, and Holy Spirit. The Trinity is therefore cast within the theme of hospitality. This is not simply Abraham’s hospitality, either. Notice that there is an open space at the table. The Holy Trinity is hospitable toward us. We are invited into relationship with the Trinity.
Our relationship with the Trinity, moreover, should inform our relationships with other people. As we are invited into relationship with the Trinity, we should invite others into this relationship through our own actions and attitudes of hospitality. In other words, the Trinitarian faith is inseparable from hospitality—God’s hospitality toward us, and our hospitality toward others. The Trinitarian faith is not just a form of metaphysical speculation. It is a claim that God puts on our lives and an ethical responsibility based upon God’s reception of us into the communion of the Father, Son, and Holy Spirit.
David F. Watson 
Thank you David.
With the current renaissance in Trinitarian thinking, the church has finally started to realize that the Trinity is the very grammar and script of Christian theology and practice. Professors and pastors need to breakdown that script into each of its parts for the members of the body of Christ so they can participate in God's cosmic drama.
Pete, I don't know how we can do Christian theology without that grammar and script.