Origen on God being mind and perhaps transcending mind, and thus only comprehensible by other minds

"Since we affirm that the God of the universe is mind, or that He transcends mind and being, and is simple and invisible and incorporeal, we would maintain that God is not comrehended by any being other than that made in the image of that mind." (Con. Cel. VII,37)

Origen on our lack of knowledge about God's characteristics in a transcendent sense

"[...]if we understand the words of which we know as applying to everything, we know of many characteristics which may be predicated of God. For He possesses virtue and blessedness and divinity. But if anyone were to understand in a more transcendent sense the words of which we know, since all that we know is inferior to God as He really is, it is not wrong that we also should accept the view that God has no characteristics of which we know. The attributes of God are superior to any which are known not only to human nature, but even by the nature of beings who haven risen beyond it." (Con. Cel. VI,62)