On Idolatry 20

But since the life of divine discipline is endangered not only by deeds but also by words (for as it is written, “Behold the man and his deeds,” so too, “By your mouth you will be justified”), we must remember that the inroad of idolatry is to be guarded against in words as well, whether it comes from the fault of habit or of timidity. The law forbids the gods of the nations to be named: not, of course, so that we should not pronounce their names, which daily intercourse forces us to say. For it must very often be said: “You will find him in the temple of Aesculapius,” and “I live in the street of Isis,” and “He has been made priest of Jupiter,” and many other things of this kind, since names of this kind are also given to men. For I do not honor Saturn if I call him by his name; I no more honor him than I honor Marcus if I call him Marcus. But it says: “Do not mention the name of other gods, nor let it be heard from your mouth.” What it commands is that we should not call them gods. For in the first part of the law too it says, “You shall not take the name of the Lord your God in vain,” that is, for an idol. So whoever has honored an idol with the name of God has fallen into idolatry. And if one must speak of gods, something must be added to make it clear that I do not call them gods. For Scripture too names gods, but adds “their” or “of the nations”; as David, when he had named gods, where he says, “But the gods of the nations are demons.” But this I have set out rather as groundwork for what follows. Moreover, it is a fault of habit to say “Mehercule” or “Medius Fidius,” with the added ignorance of some who do not know that it is an oath by Hercules. But what will swearing by those whom you have forsworn be, if not a betrayal of the faith together with idolatry? For who does not honor those by whom he swears?