IT IS NOT CHARITY TO TOLERATE ERROR: SAINT PIUS X

"The Catholic doctrine teaches us that the first duty of charity does not consist in tolerating erroneous opinions, however sincere they may be, nor in theoretical or practical indifference toward the error or vice into which we see our brethren have fallen, but rather in zeal for their intellectual and moral improvement, no less than in zeal for their material well-being. This same Catholic doctrine also teaches us that the source of love for our neighbor is found in the love of God, our common Father and the common end of the entire human family, and in the love of Jesus Christ, whose members we are, to such an extent that relieving a person in distress is doing good to Jesus Christ Himself. Every other kind of love is an illusion or a sterile and fleeting sentiment."

Encyclical Letter Notre Charge Apostolique, by His Holiness Pope Saint Pius X, August 15, 1910.