The life of God is eternal because it is personal, that is to say, it is realized as an expression of free communion, as love. Life and love are identified in the person: the person does not die only because it is loved and loves; outside the communion of love the person loses its uniqueness and becomes a being like other beings, a “thing” without absolute “identity” and “name,” without a face. Death for a person means the survival of the uniqueness of its hypostasis, which is affirmed and maintained by love.
Being As Communion – John D. Zizioulas