John Calvin (J. K. S. Reid, Calvin: Theological Treatises, pp. 192–193):
I am not unaware how difficult it is to persuade the world that God rejects and even abominates everything devised for worship by human reason. The grounds for this error are numerous. “Every one thinks highly of his own,” as the old proverb expresses it. Hence the offspring of our own brain delights us more; and besides, as Paul admits (Col. 2:23), this fictitious worship often presents some show of wisdom. Besides, as it has for the most part an external splendour which pleases the eye, it is more agreeable to our carnal nature, than that which alone God requires and approves, but which is less ostentatious. But there is nothing which so blinds the minds of men, so that they judge wrongly in this matter, as hypocrisy. For while it is incumbent on true worshippers to give heart and mind, men always want to invent a mode of serving God quite different from this, their object being to perform for him certain bodily observances, and keep the mind to themselves. Moreover, they imagine that when they thrust external pomps upon him, they have by this artifice evaded the necessity of giving themselves. This is the reason why they submit to innumerable observances which without measure and without end miserably exhaust them, and why they choose to wander in a perpetual labyrinth, rather than worship God simply in spirit and in truth.
