Calvin’s Institutes on I Corinthians 14:16-17
In his Institutes of the Christian Religion (III:20:33), Calvin adds the following: “Public prayers are not to be couched in Greek among the Latins, nor in Latin among the French or English…, but in the vulgar tongue [alias the common language] — so that all present may understand them.” Such public prayers “ought to be used for edification of the whole Church — which cannot be in the least degree benefited by a sound not understood!
“Those who are not moved by any reason of humanity or charity, ought at least to be somewhat moved by the authority of Paul…. I Cor. 14:16-17. Who, then, can sufficiently admire the unbridled audacity which the Papists have had, and still have?” For those “Papists” — contrary to the prohibition of the Apostle — chant and bray in a foreign and unknown tongue [Latin]…. For the most part, they do not understand one syllable, and…they have no wish that others understand!”