Man cannot give a definition of God in the proper sense of the word, but only a partial description. A logical definition is impossible, because God cannot be subsumed under some higher genus. At the same time it is maintained that man can obtain a knowledge of God that is perfectly adequate for the realization of the divine purpose in the life of man. However, true knowledge of God can be acquired only from the divine self-revelation, and only by the man who accepts this with childlike faith.
Berkhof, L. (1938). Systematic theology (p. 30). Grand Rapids, MI: Wm. B. Eerdmans publishing co.