42 It is a vast and endless task to examine each kind separately, and make it evident even from your religious books that you neither hold nor believe that there is any god concerning whom you have not brought forward doubtful and inconsistent statements, expressing a thousand different beliefs. But, to be brief, and avoid prolixity, it is enough to have said what has been said; it is, further, too troublesome to gather together many things into one mass, since it is made manifest and evident in different ways that you waver, and say nothing with certainty of these things which you assert.
But you will perhaps say, Even if we have no personal knowledge of the Lares, Novensiles, Penates, still the very agreement of our authors proves their existence, and that such a race takes rank among the celestial gods. And how can it be known whether there is any god, if what he is shall be wholly unknown? or how can it avail even to ask for benefits, if it is not settled and determined who should be invoked at each inquiry? For every one who seeks to obtain an answer from any deity, should of necessity know to whom he makes supplication, on whom he calls, from whom he asks help for the affairs and occasions of human life; especially as you yourselves declare that all the gods do not have all power, and that the wrath and anger of each are appeased by different rites.
Source: Against the Heathen (New Advent)