The mockery which worships God with nought but external gestures and absurd human fictions, how could we, without sin, allow to pass unrebuked? We know how much he hates hypocrisy, and yet in that fictitious worship, which was everywhere in use, hypocrisy reigned. We hear how bitter the terms in which the prophets inveigh against all worship fabricated by human rashness. But a good intention, i.e., an insane license of daring whatever man pleased, was deemed the perfection of worship. For it is certain that in the whole body of worship which had been established, there was scarcely a single observance which had an authoritative sanction from the Word of God.
We are not in this matter to stand either by our own or by other men’s judgments. We must listen to the voice of God, and hear in what estimation he holds that profanation of worship which is displayed when men, overleaping the boundaries of His Word, run riot in their own inventions. The reasons which he assigns for punishing the Israelites with blindness, after they had lost the pious and holy discipline of the Church, are two, viz., the prevalence of hypocrisy, and will-worship (ejqeloqrhskeiva), meaning thereby a form of worship contrived by man. “Forasmuch,” says he, “as the people draw near me with their mouth, and with the lips do honor me, but have removed their heart far from me, and their fear toward me is taught by the precept of men; therefore I will proceed to do a marvellous work among this people, even a marvellous work and a wonder: for the wisdom of their wise men shall perish, and the understanding of their prudent men shall be hid,” Isa. 29:13-14. When God stirred us up, a similar or worse perversity openly domineered throughout the Church. While God, then, was thundering from heaven, were we to sit quiet?
Source: Calvin, Tracts (1844; rpt. Grand Rapids: Baker, 1983), Vol. 1, pp. 189-90 at http://www.swrb.com/newslett/actualNLs/Xmas_ch2.htm