The theologian has to deal with different limitations of language. On the one hand, everything said about divine things involves some negation of things given to sense (hence we have terms like immaterial, simple (non-complex) immobile, immutable, eternal, etc. Even “good” when said of God involves some negation of goods known to sense.) On the other hand, existence does not have an essential relation to our thought, and therefore neither does it have an essential relation to our language (which allows us to speak of things like “a stone so great that God cannot lift it”)