In hearing these things we shudder indeed at so great an audacity of assertion and so great a sacrilege. And yet, Venerable Brethren, these are not merely the foolish babblings of unbelievers. There are Catholics, yea, and priests too, who say these things openly; and they boast that they are going to reform the Church by these ravings!
#10 http://www.papalencyclicals.net/Pius10/p10pasce.htm

Acting as if he were sent and inspired by God, he speaks in the name of the Trinity and then uses Scripture as a pretext for releasing the people from the law of obedience. He twists the words of holy Scripture in a bold and cunning manner in order to firmly establish his depraved ravings. He does this in order that, as St. Bernard used to say, "He might spread clouds for light or give poison for honey, or rather in the honey, creating a new Gospel for the people and laying a different foundation from the one which is already laid
# 5   http://www.papalencyclicals.net/Greg16/g16singu.htm (Condeming book Paroles d'un croyant by Félicité Robert de Lamennais)
3. These enemies of the Church usually employ a variety of deceits for turning the spirits of the Italian people away from the Catholic faith. For instance, they shamelessly affirm and cry it abroad that the Catholic religion is opposed to the glory, greatness and prosperity of the Italian nation. So they say that Protestantism should be brought in, set up and increased to replace Catholicism. Then Italy could once more acquire its former splendor of ancient, that is, pagan, times. It is hard to decide which is the more hateful aspect of this fiction of theirs -- the malice of their raving impiety or the effrontery of their lying wickedness.
http://www.papalencyclicals.net/Pius09/p9nostis.htm (NOSTIS ET NOBISCUM ON THE CHURCH IN THE PONTIFICAL STATES ENCYCLICAL OF POPE PIUS IX DECEMBER 8, 1849
Everyone must understand that such ravings and others like them, concealed in many deceitful guises, cause greater ruin to public calm the longer their impious originators are unrestrained. They cause a serious loss of souls redeemed by Christ's blood wherever their teaching spreads, like a cancer; it forces its way into public academies, into the houses of the great, into the palaces of kings, and even enters the sanctuary, shocking as it is to say so.
#7 http://www.papalencyclicals.net/Pius06/p6inscru.htm  (ON THE PROBLEMS OF THE PONTIFICATE Inscrutabile Encyclical of Pope Pius VI promulgated on December 25, 1775)

Philippians 3 :2 Beware of dogs, beware of evil workers, beware of the concision