Jean-Baptiste Chautard tells a fascinating story about Pope St. Pius X.

In The Soul of the Apostolate Dom Jean-Baptiste Chautard about Pope St. Pius X.

Chautard recounts how, on one occasion, an “eminent layman” who was spending some time with that great and holy Pope, “let fall a few biting words against an enemy of the Church.” The Pope immediately rebuked the layman, and then told him a story about a young priest that he knew. When this priest was assigned to a new parish, said the Pope, he made it his mission to visit every single family within that parish, including any Jews, Protestants, and Freemasons. However, these visits shocked his parishioners, who complained to the bishop, who in turn called the priest before him and “reprimanded him severely.”
The priest, however, calmly replied: “My Lord, … Jesus orders his pastors, in the Gospel, to bring all His sheep into the fold…How are we going to do that without going out after them? Besides, I never compromise on principles, and I confine myself to expressing my interest and my charity towards all the souls entrusted to me by God, even the ones that have gone furthest astray.”
The Pope recalled that the bishop was moved by this appeal, and granted his priest permission to continue these visits. And who was that priest? It was, the pope revealed, himself. “Therefore,” the Holy Father instructed the layman, “cling firmly to principles through thick and thin, but let your charity go out to all men, even the worst enemies of the Church.” Pope St. Pius X finished his story about the zealous young priest, saying, “The future proved that the priest was right, because he had the happiness to convert a few of these strays, and inspired all the others with a great respect for our Holy Church.”