Now observe: God is nameless because none can say or understand anything about Him. Concerning this a pagan master says that what we understand or declare about the first cause is more what we ourselves are than what the first cause is, because it is above all speech or understanding.
If I now say God is good, it is not true; rather, I am good, God is not good. I will go further and say I am better than God: for what is good can become better, and what can become better can become best of all. Now God is not good, therefore He cannot become better. And since He cannot become better, therefore He cannot become best; for these three, good, better, and best, are remote from God, since He is above them all. Thus, too, if I say God is wise, it is not true: I am wiser than He. So too if I say God is a being, that is not true: He is a transcendent being, and a superessential nothingness.
St. Dionysius says the finest thing one can say about God is to be silent from the wisdom of inner riches. So be silent and do not chatter about God, because by chattering about Him you are lying and so committing a sin. So, if you want to be without sin and perfect, don’t chatter about God. Nor should you (seek to) understand anything about God, for God is above all understanding. One master says, ‘If I had a God I could understand, I would no longer consider him God.’ So, if you understand any thing of Him, that is not He, and by understanding anything of Him you fall into misunderstanding, and from this misunderstanding you fall into brutishness, for whatever in creatures is uncomprehending is brutish. So, if you don’t want to become brutish, understand nothing of God the unutterable.
[expand]
Source: The complete mystical works of Meister Eckhart, Part One: Sermons, Sermon 96, pg. 463
[/expand]