When a man comes to himself, be it because he turns to sense-knowledge, to desire or to reason, (yes, even though he should make such progress that he strips off all likeness to brute beasts and clothes himself in man’s true nature) he neither escapes the night nor enters completely into the daylight. My soul is a trouble to me, sings the Seer, and therefore he began to be mindful of God, as of the daylight. For God is all light and in him alone no darkness can find any place. Though the holy angels find their morning in him, yet they stumble in the evening that they find in themselves; this evening of theirs and the morning of God go to make that one, first day. God alone finds the light of day in himself, and once he begins thanks to his purely gratuitous grace to shine in rational minds, he creates morning and separates light from darkness,
Grace then is the dawn of the spiritual day; it not only anticipates reason, it turns it from itself to God and leads it from the darkness of ignorance or, as previously mentioned, of weakness and even ill-will, into the daylight of wisdom, virtue and justice–the day, in other words, of Christ our Lord.
From Isaac of Stella’s Second Sermon for Septugesima Sunday, v. 5, 6