Athanasius of Alexandria actually has a lot to say about the divine nature. He says that it is fruitful. He says that its essence and its existence are identical. He says that it is simple and infinite. And yet, he also says that the divine nature is, in itself, unknowable to us. We have nothing with which to compare it. We can only speak about it according to how God has revealed Himself– and even then, we can only do this on a limited basis.
Writing in his Against the Arians, Athanasius says this:
Nor must we ask why the Word of God is not such as our word, considering God is not such as we, as has been before said; nor again is it right to seek how the word is from God, or how He is God’s radiance, or how God begets, and what is the manner of His begetting. For a man must be beside himself to venture on such points; since a thing ineffable and proper to God’s nature, and known to Him alone and to the Son, this he demands to be explained in words. It is all one as if they sought where God is, and how God is, and of what nature the Father is. But as to ask such questions is irreligious, and argues an ignorance of God, so it is not holy to venture such questions concerning the generation of the Son of God, nor to measure God and His Wisdom by our own nature and infirmity. Nor is a person at liberty on that account to swerve in his thoughts from the truth, nor, if any one is perplexed in such inquiries, ought he to disbelieve what is written. For it is better in perplexity to be silent and believe, than to disbelieve on account of the perplexity: for he who is perplexed may in some way obtain mercy, because, though he has questioned, he has yet kept quiet; but when a man is led by his perplexity into forming for himself doctrines which beseem not, and utters what is unworthy of God, such daring recurs a sentence without mercy. For in such perplexities divine Scripture is able to afford him some relief, so as to take rightly what is written, and to dwell upon our word as an illustration; that as it is proper to us and is from us, and not a work external to us, so also God’s Word is proper to Him and from Him, and is not a work; and yet is not like the word of man, or else we must suppose God to be man. (Against the Arians 2.18.36)