"From this Gregory turned to the main problem: how to combine the two affirmations, that we humans know God and that God is by nature unknowable. Gregory answered: we know the energies of God, but not His essence. This distinction between God's essence (ousia) and His energies goes back to the Cappodacian Fathers. 'We know our God from His energies,' wrote St. Basil, 'but we do not claim that we can draw near to His essence. For His energies come down to us, but His essence remains unapproachable.' Gregory accepted this distinction. He affirmed, as emphatically as any exponent of negative theology, that God is in essence absolutely unknowable. 'God is not a nature,' he wrote, 'for He is above all nature; He is not a being, for He is above all beings...No single thing of all that is created has or ever will have even the slightest communion with the supreme nature or nearness to it.' But however remote from us in His essence, yet in His energies God has revealed Himself to us. These energies are not something that exists apart from God, not a gift which God confers upon humans; they are God Himself in His action and revelation to the world. God exists complete and entire in each of His divine energies. The World, as Gerard Manley Hopkins said, is charged with the grandeur of God; all creation is a gigantic Burning Bush, permeated but not consumed by the ineffable and wondrous fire of God's energies.
"It is through these energies that God enters into a direct and immediate relationship with humankind. In relation to us humans, the divine energy is in fact nothing else than the grace of God; grace is not just a 'gift' of God, not just an object which God bestows on humans, but a direct manifestation of the living God Himself, a personal encounter between creature and Creator. 'Grace signifies all the abundance of the divine nature, in so far as it is communicated to men.' When we say that the saints have been transformed or 'deified' by the grace of God, what we mean is that they have a direct experience of God Himself. They know God - that is to say, God in His energies, not in His essence." - Kallistos Timothy Ware, The Orthodox Church, p. 67-68