In this chapter I will describe the main difference between classical metaphysics and Christian ontology. This distinction is useful to understand the role played by the body in the prayer; moreover these two different ontologies can cast some light on the different path to ?deification? both in ancient philosophy and in Christian Theology. This task will be achieved through the analysis of Gregory of Nyssa’s thought, specifically his conception of Trinity. This theological argument renews the notion of relation, which from now on cannot be held as an accidental property anymore, rather as an essential one. It will be shown how the theological debate around Trinity reflected itself in a whole new ontological framework, allowing for a different conception of relation and love, and shifting the paradigm of deification as an intellectual path to a personal dialogue, involving heart, intellect, and passion, therefore body.