43 For if this deity requires a black, that a white skin; if sacrifice must be made to this one with veiled, to that with uncovered head; this one is consulted about marriages, the other relieves distresses—may it not be of some importance whether the one or the other is Novensills, since ignorance of the facts and confusion of persons displeases the gods, and leads necessarily to the contraction of guilt? For suppose that I myself, to avoid some inconvenience and peril, make supplication to any one of these deities, saying, Be present, be near, divine Penates, you Apollo, and you, O Neptune, and in your divine clemency turn away all these evils, by which I am annoyed, troubled, and tormented: will there be any hope that I shall receive help from them, if Ceres, Pales, Fortune, or the genius Jovialis, not Neptune and Apollo, shall be the dii Penates?
Or if I invoked the Curetes instead of the Lares, whom some of your writers maintain to he the Digiti Samothracii, how shall I enjoy their help and favour, when I have not given them their own names, and have given to the others names not their own? Thus does our interest demand that we should rightly know the gods, and not hesitate or doubt about the power, the name of each; lest, if they be invoked with rites and titles not their own, they have at once their ears stopped against our prayers, and hold us involved in guilt which may not be forgiven.
Source: Against the Heathen (New Advent)