9 “For the Father loves the Son, and shows Him all things that Himself does.” Here is that “shows.” “Shows,” as it were, to whom? Of course, as to one that sees. We return to that which we cannot explain, how the Word sees. Behold, man was made by the Word; but man has eyes, ears, hands, various members in the body: he is able by the eyes to see, by the ears to hear, by the hands to work; the members are diverse, their offices diverse. One member cannot do the office of another; yet, by reason of the unity of the body, the eye sees both for itself and for the ear, and the ear hears for itself and for the eye.
Are we to suppose that something like this holds good in the Word, seeing all things are by Him; and Scripture has said in the psalm, “Understand, you brutish among the people; and you fools, at length be wise. He that planted the ear, shall He not hear? And He that formed the eye, shall He not see?” Hence, if the Word is He that formed the eye, for all things are by the Word; if the Word is He that planted the ear, for all things are by the Word: we cannot say the Word does not hear, the Word does not see; lest the psalm reprove us, and say, “Fools, at length be wise.”
Therefore, if the Word hears and sees, if the Son hears and sees, are we yet to search for eyes and ears in Him in separate places? Does He by one part hear, by another see; and cannot His ear do what His eye does; and cannot His eye do what His ear can? Or is He not all sight, all hearing? Perhaps yes; nay, not perhaps, but truly yes; while, however, that seeing of His, and that hearing of His, is in a way far other than it is with us. Both to see and to hear exist together in the Word: seeing and hearing are not diverse things in Him; but hearing is sight, and sight is hearing.
Source: Tractates on the Gospel of John (New Advent)