80 He feeds the prophet, who understands and keeps the things that are written. Our faith gives him sustenance, our progress gives him nourishment; he feeds upon our minds and senses, his discourse is nourished by our understanding. In the morning we give him bread, who, being placed in the light of the Gospel, bestow on him the settled strength of our hearts. By these things he is nourished, by these he is strong, with these he fills the mouths of those who fast, to whom the unbelief of the Jews supplied no food of faith. To them every prophetic utterance is but fasting diet, the interior richness of which they do not see; empty and thin, such as cannot fatten their jaws.
Source: Letters (New Advent)