For I did not know that the soul needs to be enlightened by light from outside itself, so that it can participate in truth, because it is not itself the nature of truth.

All truth and understanding is a result of a divine light which is God Himself.

No one knows what he himself is made of, except his own spirit within him, yet there is still some part of him which remains hidden even from his own spirit; but you, Lord, know everything about a human being because you have made him...Let me, then, confess what I know about myself, and confess too what I do not know, because what I know of myself I know only because you shed light on me, and what I do not know I shall remain ignorant about until my darkness becomes like bright noon before your face.

A very weighty argument is this namely, that neither does the light which descends from thence, chiefly upon the world , mix itself with anything, nor admit of dirtiness or pollution, but remains entirely, and in all things that are, free from defilement, admixture, and suffering.