41 It was once usual, in speaking allegorically, to conceal under perfectly decent ideas, and clothe with the respectability of decency, what was base and horrible to speak of openly; but now venerable things are at your instance; vilely spoken of, and what is quite pure is related in filthy language, so that that which vice formerly concealed from shame, is now meanly and basely spoken of, the mode of speech which was fitting being changed. In speaking of Mars and Venus as having been taken in adultery by Vulcan's art, we speak of lust, says my opponent, and anger, as restrained by the force and purpose of reason.
What, then, hindered, what prevented you from expressing each thing by the words and terms proper to it? Nay, more, what necessity was there, when you had resolved to declare something or other, by means of treatises and writings, to resolve that that should not be the meaning to which you point, and in one narrative to take up at the same time opposite positions— the eagerness of one wishing to teach, the niggardliness of one reluctant to make public? Was there no risk in speaking of the gods as unchaste?
The mention of lust and anger, my opponent says, was likely to defile the tongue and mouth with foul contagion. But, assuredly, if this were done, and the veil of allegorical obscurity were removed, the matter would be easily understood, and by the same the dignity of the gods would be maintained unimpaired. But now, indeed, when the restraining of vices is said to be signified by the binding of Mars and Venus, two most inconsistent things are done at the very same time; so that, on the one hand, a description of something vile suggests an honourable meaning, and on the other, the baseness occupies the mind before any regard for religion can do so.
Source: Against the Heathen (New Advent)