God both is and is said to be the nature of all beings, in so far as all partake of Him and subsist by means of this participation: not however by participation in His nature - far from it - but by participation in His energy. In this sense He is Being of all beings, the Form that is in all forms as the Author of form, the Wisdom of the wise and, simply, the All in all things. Moreover, He is not nature, because He transcends nature; He is not a being, because He transcends every being; and He is not nor does He possess a form because He transcends form.
“Topics of Natural and Theological Science”, Philokalia Vol. 4 [emphasis added]
This is something of what I was getting at when I called God "that which exists as the ground of conceptual and ontological relationality (i.e., as the transcendent conceptual and ontological 'limit value') for all things".