Saturdays with Calvin #4

It is easy to see how superstition, with its false glosses, mocks God, while it tries to please him. Usually fastening merely on things on which he has declared he sets no value, it either contemptuously overlooks, or even undisguisedly rejects, the things which he expressly enjoins, or in which we are assured that he takes pleasure. Those, therefore, who set up a fictitious worship, merely worship and adore their own delirious facies; indeed, they would never dare so to trifle with God, had they not previously fashioned him after their own childish conceits.

Hence that vague and wandering opinion of Deity is declared by an apostle to be ignorance of God: "How be it, then, when ye know not God, ye did service unto them which by nature are no gods." And he elsewhere declares, that the Ephesians were "without God" (Eph. 2:12) at the time when they wandered without any correct knowledge of him. It makes little difference, at least in this respect, whether you hold the existence of one God , or a plurality of gods, since, in both cases alike, by departing from the one true God, you have nothing left but an execrable idol.

Institutes of the Christian Religion 1.4.3, John Calvin, translated by Henry Beveridge, Hendrickson, pg. 13.  (emphasis mine)