Pope Gregory XVI

"Now We consider another abundant source of the evils with which the Church is afflicted at present: indifferentism. This perverse opinion is spread on all sides by the fraud of the wicked who claim that it is possible to obtain the eternal salvation of the soul by the profession of any kind of religion, as long as morality is maintained. Surely, in so clear a matter, you will drive this deadly error far from the people committed to your care. With the admonition of the apostle that “there is one God, one faith, one baptism” may those fear who contrive the notion that the safe harbor of salvation is open to persons of any religion whatever."

"This shameful font of indifferentism gives rise to that absurd and erroneous proposition which claims that liberty of conscience must be maintained for everyone. It spreads ruin in sacred and civil affairs, though some repeat over and over again with the greatest impudence that some advantage accrues to religion from it. “But the death of the soul is worse than freedom of error,” as Augustine was wont to say. When all restraints are removed by which men are kept on the narrow path of truth, their nature, which is already inclined to evil, propels them to ruin. Then truly “the bottomless pit” is open from which John saw smoke ascending which obscured the sun, and out of which locusts flew forth to devastate the earth. Thence comes transformation of minds, corruption of youths, contempt of sacred things and holy laws—in other words, a pestilence more deadly to the state than any other. Experience shows, even from earliest times, that cities renowned for wealth, dominion, and glory perished as a result of this single evil, namely immoderate freedom of opinion, license of free speech, and desire for novelty."

"We must include that harmful and never sufficiently denounced freedom to publish any writings whatever and disseminate them to the people, which some dare to demand and promote with so great a clamor. We are horrified to see what monstrous doctrines and prodigious errors are disseminated far and wide in countless books, pamphlets, and other writings which, though small in weight, are very great in malice. We are in tears at the abuse which proceeds from them over the face of the earth. Some are so carried away that they contentiously assert that the flock of errors arising from them is sufficiently compensated by the publication of some book which defends religion and truth. Every law condemns deliberately doing evil simply because there is some hope that good may result. Is there any sane man who would say poison ought to be distributed, sold publicly, stored, and even drunk because some antidote is available and those who use it may be snatched from death again and again? The Church has always taken action to destroy the plague of bad books."

"We have learned that certain teachings are being spread among the common people in writings which attack the trust and submission due to princes; the torches of treason are being lit everywhere. Care must be taken lest the people, being deceived, are led away from the straight path. May all recall, according to the admonition of the apostle that “there is no authority except from God; what authority there is has been appointed by God. Therefore he who resists authority resists the ordinances of God; and those who resist bring on themselves condemnation.” Therefore both divine and human laws cry out against those who strive by treason and sedition to drive the people from confidence in their princes and force them from their government."

"Nor can We predict happier times for religion and government from the plans of those who desire vehemently to separate the Church from the state, and to break the mutual concord between temporal authority and the priesthood. It is certain that that concord which always was favorable and beneficial for the sacred and the civil order is feared by the shameless lovers of liberty."