II. In matters of Faith human rhetoric is out of place.
For if it be always free for human fancies to assert themselves in dispute, there never will be wanting men who will dare to oppose the Truth, and to put their trust in the glib utterances of this world's wisdom, whereas the Christian Faith and wisdom knows from the teaching of our Lord Jesus Christ Himself how strictly it ought to shun this most harmful vanity. For when Christ was about to summon all nations to the illumination of the Faith, He chose those who were to devote themselves to the preaching of the Gospel not from among philosophers or orators, but took humble fishermen as the instruments by which He would reveal Himself, lest the heavenly teaching, which was of itself full of mighty power, should seem to need the aid of words.
And hence the Apostle protests and says, “For Christ sent me not to baptize but to preach the Gospel, not in wisdom of words lest the cross of Christ should be made void; for the word of the cross is to them indeed that perish foolishness, but to those which are being saved it is the power of God. For it is written, I will destroy the wisdom of the wise and the prudence of the prudent will I reject. Where is the wise? Where is the scribe? Where is the inquirer of this age? Has not God made foolish the wisdom of this world?”
For rhetorical arguments and clever debates of man's device make their chief boast in this, that in doubtful matters which are obscured by the variety of opinions they can induce their hearers to accept that view which each has chosen for his own genius and eloquence to bring forward; and thus it happens that what is maintained with the greatest eloquence is reckoned the truest. But Christ's Gospel needs not this art; for in it the true teaching stands revealed by its own light: nor is there any seeking for that which shall please the ear, when to know Who is the Teacher is sufficient for true faith.
Source: Letters (New Advent)