Augustine of Hippo — as excerpted in the Catena Aurea on John 8:31-36

“(Tr. xli. 1) As if to say: Whereas ye have now belief, by continuing, ye shall have sight. (xl. 9.). For it was not their knowledge which made them believe, but rather their belief which gave them knowledge. Faith is to believe that which you see not: truth to see that which you believe? By continuing then to believe a thing, you come at last to see the thing; i. e. to the contemplation of the very truth as it is; not conveyed in words, but revealed by light. The truth is unchangeable; it is the bread of the soul, refreshing others, without diminution to itself; changing him who eats into itself, itself not changed. This truth is the Word of God, which put on flesh for our sakes, and lay hid; not meaning to bury itself, but only to defer its manifestation, till its suffering in the body, for the ransoming of the body of sin, had taken place.”