Once, chassidim distanced from themselves a certain individual who sinned in a particularly disgusting manner. When the Alter Rebbe, Rabbi Shneur Zalman of Liadi heard about the actions of the chassidim, he responded: “You do not appreciate the effect of even the externality of Chassidus. Being in a chassidic shul will ensure that he will be stimulated by the environment. No, no. Instead of pushing him away, you should bring him closer. Maybe as a result, he will sin one time less.” The Alter Rebbe continued, saying: “The amount of pleasure that G-d derives when a Jew does one less sin is unfathomable.”
(Ramach Osiyos, 84)