Gregory the Great — on Ezek 3:3 (Homilies on Ezekiel, Book 1, Homily 10)

“And it often happens that such persons, through the gift of heavenly grace, also receive the word of doctrine, and from the food of truth which they themselves sweetly ruminate upon inwardly, they also sweetly feed their neighbors. From their mouth, indeed, preaching is sweet to their hearers insofar as their actions are not contrary to their preaching, because they draw from their own life what they bestow upon their neighbors through their tongue. Hence here too the prophet rightly adds: "And I ate it, and it became in my mouth sweet like honey." The book which filled his inward parts became sweet in his mouth like honey, because those who have learned to truly love the Almighty Lord in the depths of their heart know how to speak sweetly about Him. Indeed, Sacred Scripture is sweet in the mouth of one whose inward life is filled with His commandments, because it is pleasant to speak for one upon whom it has been inwardly impressed for living. For speech has no sweetness when a reprobate life gnaws at the conscience within. Hence it is necessary that whoever speaks the word of God should first attend to how he lives, so that he may afterwards gather from his life what he should say and how he should say it. For in preaching, the conscience of holy love builds up more than the exercise of speech, because by loving heavenly things the preacher reads within himself how he may persuade others that earthly things ought to be despised. For he who weighs his life inwardly and builds up others outwardly by admonishing them through his example, as it were dips the pen of his tongue in his heart, in that he writes externally to his neighbors with the hand of his word. Hence the admirable preacher, when he said many things in exhorting his disciples, because he bore no contradiction within himself from his conscience, confidently added: "If there is any virtue, if there is any praise of discipline, think on these things; what you have both learned, and received, and heard, and seen in me, do these things, and the God of peace shall be with you."”