It does not belittle the gospel to say that it was preached without wisdom. On the contrary, this is the gospel’s great glory, the clearest sign that it is divine and that it comes from heaven. When demonstration is made by the wisdom of human words, the worse argument often overcomes the better one, because the one who argues for it has greater rhetorical skills. But in this case it is not so, because the Spirit does not enter an unclean soul, nor can he ever be overcome, however much clever speech is used to attack him. The demonstration by works and signs is more powerful than mere words.
from Homilies on the Epistles of Paul to the Corinthians 6.3