ACC ~ Titus 3 v9

THE FAITHFUL SHEPHERD. AMBROSE: Blessed is that servant [Paul] who can say: “I have fed you with milk and not with meat; for until now you were not able to bear it.” … Yet he—being so great a man and chosen by Christ for the care of his flock in order to strengthen the weak and to heal the sick—rejects immediately after a single admonition a heretic from the fold entrusted to him. This he does for fear that the taint of one erring sheep might infect the whole flock with a spreading sore. He further bids that foolish questions and contentions be avoided. OF THE CHRISTIAN FAITH 5, PROLOGUE 3-4.

DO NOT SOW ON A ROCK. CHRYSOSTOM: “Contentions,” he means, with heretics. He would not have us labor to no purpose, where nothing is to be gained, for they end in nothing. For when a man is perverted and predetermined not to change his mind, whatever may happen, why should you labor in vain, sowing upon a rock, when you should spend your honorable toil upon your own people, in discoursing with them upon almsgiving and every other virtue? HOMILIES ON TITUS 6.

Tit