The Orthodox Church believes that we know God by what He does and we have believed this for a very long time. We believe that on the one hand God is approachable and knowable and on the other hand we believe that in is essence God is unknowable.
Gerald Manley Hopkins poem, “As Kingfishers Catch Fire” captures this truth that we know God by what He does. What He does is who He is.
As kingfishers catch fire, dragonflies draw flame;
As tumbled over rim to roundy wells
Stones ring; like each tucked string tells, each hung bell’s
Bow swung finds tongue to fling out broad its name;
Each mortal thing does one thing and the same:
Deals out that being indoors each one dwells;
Selves – goes its self; myself it speaks and spells,
Crying What I do is me: for that I came
I say more: the just man justices;
Keeps grace: that keeps all his going graces;
Acts in God’s eye what in God’s eye he is –
Christ. For Christ plays in ten thousand places,
Lovely in limbs, and lovely in eyes not his
To the Father through the feature of men’s faces.
Just as birds and insects in what they are, are drawn to fire. What they do is who they are. And just as stones fall down mountains and when they fall they crash. What they do is who they are. And just as bells ring when their strings are pulled and they cannot help but fling out their name – that is just what they do. And what they do is who they are. It is the same with Christ. What he does is who he is. He loves, redeems, saves and he is present and calling us to Himself. That is who he is! The Way, Truth and Life! He cannot not do who He is.
“St. Gregory addressed this problem of knowing an unknowable God and 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 Cappadocian Fathers. “We know our God from His energies,’ wrote Saint 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” (Letter 234, 1). 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” (P.G. cl, 1176c). But however remote from us in His essence, yet in His energies God has revealed Himself to men. These energies are not something that exists apart from God, not a gift, which God confers upon men: 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. (Compare Maximus, Ambigua, P.G. xci, 1148d).
It is through these energies that God enters into a direct and immediate relationship with mankind. In relation to man, 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 men, but a direct manifestation of the living God Himself, a personal confrontation between creature and Creator. “Grace signifies all the abundance of the divine nature, in so far as it is communicated to men” (V. Lossky, The Mystical Theology of the Eastern Church, p. 162). 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.” Bishop Kallistos Ware, The Orthodox Church.