I come now to ceremonies, which, while they ought to be grave attestations of divine worship, are rather a mere mockery of God. A new Judaism, as a substitute for that which God has distinctly abrogated, has again been reared up by means of numerous puerile extravagancies, collected from different quarters; and with these have been mixed up certain impious rites, partly borrowed from the heathen, and more adapted to some theatrical show than to the dignity of our religion. The first evil here is, that an immense number of ceremonies, which God had by his authority abrogated, once for all, have been again revived. The next evil is, that while ceremonies ought to be living exercises of piety, men are vainly occupied with numbers of them that are both frivolous and useless. But by far the most deadly evil of all is, that after men have thus mocked God with ceremonies of one kind or other, they think they have fulfilled their duty as admirably as if these ceremonies included in the whole essence of piety and divine worship.
Source: Calvin, Tracts (1844; rpt. Grand Rapids: Baker, 1983), Vol. 1, pp. 131-32 at http://www.swrb.com/newslett/actualNLs/Xmas_ch2.htm