Eastern Orthodox theology makes a fundamental distinction—systematically articulated by St. Gregory Palamas in the 14th century—between God's entirely unknowable, transcendent essence (ousia) and his uncreated divine energies (energeiai), through which God genuinely communicates himself to creation. God in his essence is absolutely beyond creaturely comprehension; but through his energies (grace, love, light), he truly shares himself with human beings, enabling theosis without compromising divine transcendence.

Apophatic (negative) theology—the recognition that God surpasses all human concepts—is central to Orthodox theological method. What cannot be said of God is as important as what can be said. This apophatic tradition, rooted in St. Dionysius the Areopagite and the Cappadocian Fathers, safeguards the genuine mystery of God against over-confident rationalism. The uncreated Light seen by the disciples at the Transfiguration (Matthew 17) is, in Orthodox theology, the divine energies themselves—and the goal of hesychast prayer is to participate in this light.