Dionysius on God+Angels in Chapter 5 of Pico's De Ente

God is all things, and is all things most eminently and most perfectly. This would not be unless he so included the perfections of all things in himself that he excluded from himself whatever pertains to imperfections in things. We can, however, define what is imperfect in the things that are.
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That human knowledge which is called rational is, in turn, imperfect knowledge because it is vague, uncertain, shifting, and laborious. Add the intellectual knowledge of divine minds, which the theologians call angels. Even that is imperfect knowledge, at least because it seeks outside itself what it does not possess fully within itself, i.e., the light of truth which it lacks, and by which is is perfected.
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the life of the angels is not perfect. Unless the vivifying ray of divine light constantly warmed it, it would all fall into nothingness. The same is true of other things. Therefore, when you say that God is knowing and living, notice first that the life and cognition which are ascribed to him are understood as free from all these imperfections, but this is not enough. There remains another imperfection.
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God is infinite perfection of every sort, but not merely in that he includes all such particular and infinite perfections in himself. In that case he would not be most simple, nor would those things which are in him be infinite. He would be one infinite compounded from many things infinite in number but finite in perfection. To say or think this of God is impious.
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since God is he who is all things when all imperfection is removed, surely when you have taken away from all things both the imperfection which is under their genus and also the particularity of their genus, what remains is God. Consequently, God is being itself, the one itself, the good itself, and likewise truth itself.
We have now advanced two steps, ascending to the darkness which God inhabits, purging from the divine names all blemish that is from the imperfection of the thing signified.

Ch5 48 God is infinite perfection of every sort, but not merely in that he includes all such particular and infinite perfections in himself. In that case he would not be most simple, nor would those things which are in him be infinite. He would be one infinite compounded from many things infinite in number but finite in perfection. To say or think this of God is impious.

Ch5 48 Let us therefore remove from life not only that which makes it imperfect life but also that which makes it merely life, and likewise from knowledge and from the other names we give to God; and then what shall be left over from all these will necessarily be such as we wish God to be understood, that is, one, most perfect, inifinite, most simple.

Ch5 49 God is being itself, the one itself, the good itself, and likewise truth itself.

Ch5 50 Let us rise to the fourth step and enter the light of ignorance, and, blinded by the darkness of divine splendor let us cry out with the Prophet, “I have become weak in the courts, O Lord,” finally saying only this about God, that he is unintelligibly and ineffably above everything most perfect which we can either speak or conceive of him. Then we place God most eminently above even unity, goodness, truth, and existence, which we conceive. Dionysius the Areopagite saw this… he spoke as he could about God in a very holy way, as if he were already in the cloud. After some other things on the subject, he cried out, “He is not truth, not kingdom, nor wisdom, nor one, nor unity, nor deity, nor goodness, nor spirit, so far as we can know him… neither is there any affirmation or negation of it.” [long quote from Dionysius]

Ch5 51 Dionysius and the Platonists deny that life and intellect and wisdom and things similar to these are in God. God himself, by his unique perfection, which is his infinity, his diety, which he himself is, unites and collects all the perfection of these things, which in them is many and divided. God does not unite these perfections as one from among many, but as one prior to these many. Consequently, some other thinkers, and especially the Peripatetics, whom the Parisian theologians follow in almost all matters as far as is allowed, grant that all these perfections are in God. When we say and believe this we not only say and believe rightly, but we do this in agreement with those who deny these perfections.

Ch5 52 [on calling God intellect] Even Dionysius, although he says the same thing as Plato, also does not deny with Aristotle that God is not ignorant of himself and other things. Consequently, if he knows himself, he is intellect and intelligible… if we understand these perfections as individual, or if, when we say intellect, we signify the nature that tends outside itself to the intelligible as to another thing, then Aristotle, no less than the Platonists, will most steadily deny that God is also intellect and intelligible. [900 heretical conclusion, defended in Apology, here further explained]