Eternity [the Principle as distinguished from the property of everlastingness] is that substratum carrying that state in manifestation. Eternity, thus, is of the order of the supremely great; it proves on investigation to be identical with God.
Plotinus argues that Eternity is not mere everlastingness but the divine substratum itself in its self-manifesting perdurance, making it ontologically identical with God.
, The Six Enneads, 270thesis