Yet have there been men, who, deceived by the vanity of their hearts, maintained that the Father is invisible, the Son visible. Now if they call the Son visible, with respect to His connexion with the flesh, we object not; it is the Catholic doctrine. But it is madness in them to say He was so before His incarnation; i. e. if it be true that Christ is the Wisdom of God, and the Power of God. The Wisdom of God cannot be seen by the eye. If the human word cannot be seen by the eye, how can the Word of God?
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).
Also cites: Tr. iii. c. 18