The Six Books of Proclus on the Theology of Plato, Volume 2

For knowing itself, it is evident that it is converted to itself in energy. For that which knows and that which is known are one. And the knowledge of itself is directed to itself as to that which is known. This knowledge also as pertaining to that which knows is a certain energy; but it is the knowledge of itself directed to itself, because it is gnostic of itself. Moreover, that it is converted to itself essentially, if it is so in energy, has been demonstrated. For every thing which by energizing is converted to itself, has also an essence verging to, and subsisting in itself.