HaRav Yehoshua Heller zt"l was a talmid of HaRav Yisroel Salanter zt"l. He served as the rov in the Lithuanian town of Flongian.
One time, on Rosh Hashana, he spoke about the terrible breach of consorting with gentiles. In the midst of his talk, R' Chaim the milkman burst into tears. Everyone knew why. His daughter was about to turn her back on her faith and marry a gentile. On the very morrow, the milkman brought his daughter to HaRav Yehoshua that he try to dissuade her.
R' Yaakov Mark describes the scene: the brokenhearted father stands, wringing his hands in distress, his eyes beseeching, and the daughter standing in the middle. HaRav Yehoshua Heller turns to the daughter and asks her: "Do you really want to leave Yiddishkeit?"
And she replies, "Chas vesholom! I don't want to abandon my faith but I can't help seeing how my parents, who are so vigilant in keeping the mitzvos, live in constant self-censure, and keep sighing over the sins they have committed, fearing for their portion in Olam Haba, while gentiles live their lives without guilt. Each Sunday their priest describes what a paradise awaits them! And even if a gentile sins, his priest absolves him! So tell me, HaRav, isn't it better to live the life of a gentile who enjoys the pleasures of this life and is promised paradise as well?"
HaRav Yehoshua Heller listened to her and replied, "You are mistaken. Your argument is very old. Yitzchok Ovinu had two sons, Esav and Yaakov. He blessed Esav with the best of this world, while granting Yaakov the bliss of the World to Come, a world that is all-good.
"If Esav were to realize that he was denied reward in the Next World, he would lose all desire and pleasure in this world, but this was already guaranteed in the blessing he received. This is why Hashem saw to it that he be deceived that he does have reward awaiting him in Olam Haba. Thus, he is guaranteed enjoyment in this world.
"Yaakov is convinced that he will enjoy the reward of Olam Haba, as is every Jew. But he is not promised an easy life here and must worry all the time lest he forfeits his Olam Haba. While this diminishes his earthly life, he can still hope for eternal goodness."
Lithuanian Jewry are no more. Even if the priest does not promise eternal reward to his flock, there are still those heretics and secularists who promise eternal life without guilt. Let them enjoy their delusions in this world. We, the Torah-observant people, are satisfied with our constant self reproof. Our path leads to eternal reward which "no eye has perceived, save for You, and which awaits us."