From "The Divine Names" by Dionysius the Areopagite as paraphrased by the translator. Dionysius was initiated by Paul in Athens and can be referenced in the Acts of the Apostles.
From Chapter 5:
"The Ultimate Godhead is reached only by the Negative Path and known only by unknowing. The Affirmative Path of philosophical knowledge leads only to the differentiated manifestations of the Godhead: e.g the Trinity, in its creative and redemptive activities, is known by the Affirmative Method, but behind these activities and the faculty for them lies an ultimate Mystery where the Persons transcend Themselves and are fused (though not confused)."
Specifically Dionysius states "But this much we must say, that it is not the purpose of our discourse to reveal the Super-Essential Nature (for this is unutterable, nor can we know It, or in anywise express It, and it is beyond even the Unity), but only to celebrate the Emanation of the Absolute Divine Essence into the universe of things."
Likewise, in "The Mystical Theology", chapter 1, of Dionysius he states "For, by the unceasing and absolute renunciation of thyself and all things, thou shalt in pureness cast all things aside, and be released from all, and so shall be led upwards to the Ray of that divine Darkness which exceedeth all existence."
I'm sure this is fairly(almost) clear to the reader as in these presentations the nature of evil is likewise clarified (previous chapters) but I thought the above was more germane.