3. We are not to fashion God according to our own whim
Thus is overthrown that vain defense with which many are wont to gloss over their superstition. For they think that any zeal for religion, however preposterous, is sufficient. But they do not realize that true religion ought to be conformed to God’s will as to a universal rule; that God ever remains like himself, and is not a specter or phantasm to be transformed according to anyone’s whim. One can clearly see, too, how superstition mocks God with pretenses while it tries to please him. For, seizing almost solely upon what God has testified to be of no concern to himself, superstition either holds in contempt or else openly rejects that which he prescribes and enjoins as pleasing to himself. Thus all who set up their own false rites to God worship and adore their own ravings.
The Institutes of the Christian Religion (Louisville, KY; Westminster John Knox Press; 1974) Vol. 1.4.3. p. 49