For the ways of Hashem are straight, the righteous walk in them, and the sinners stumble in them. (Hoshea 14:10)
Rabbi Yehuda Greenwald, rav of Satmar, wrote a letter in 1913 urging the rabbis of his time not to join the new organization Agudath Israel. Agudah had integrated into its membership and leadership many non-Orthodox Jews, and they were influencing the platform and goals of the organization. The Hungarian rabbis, knowing from experience in their own country the dangers of joining the irreligious, refused to join Agudah. Rabbi Greenwald quoted the above verse, and wrote that the Chasam Sofer said that it could be punctuated as follows: "For the ways of Hashem are straight; however if the righteous walk in them together with sinners, they will stumble in them." King David began the book of Tehillim with the words, "Fortunate is the man who did not walk in the counsel of the wicked, or stand in the way of sinners, or sit in a place of scorners." Certainly he did not mean to warn against joining the wicked and doing as they do – that is obviously wrong. Rather his intent was to warn against joining the wicked even when they propose some plan for the sake of Heaven, to uphold the Torah. (Shailos Utshuvos Zichron Yehuda, Siman 200)
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The Chovos Halevavos writes about this verse "the sinners stumble in them" in Shaar Yichud Hamaaseh, Chapter 5: "If you are a Torah scholar, the evil inclination will try to cause you to err in your wisdom and actions using arguments and proofs from logic, from Scripture and tradition. If your mind is clear and strong you will see the fallacy in his proofs, but if not he will convince you and overpower you more completely than he does others, since he is leading you with proofs from the Torah on which you rely. Once he has your confidence he will lead you on to rely on him even in matters you do not understand, and eventually you will believe in complete falsehood. Then your wisdom will be your own enemy and your mind the cause of your downfall… as it says, 'For the ways of Hashem are straight, and the righteous walk in them, but the sinners stumble in them.' For wisdom, when guided in the proper path, is the cure for every sickness, but when taken off the path, is itself a sickness that has no cure and does not heal."
This same concept is explained in Sanhedrin 38b. The Gemora there quotes the Mishnah in Avos (2:14): "Be diligent in Torah study, and know what to answer to a heretic." Rabbi Yochanan said, "This was only said regarding a gentile heretic, but to a Jewish heretic one should not reply, for he will only become worse." Rashi explains that a "gentile heretic" means a gentile who tries to bring proofs to the Jewish heretics from the words of the Torah. Since he is not learned in Torah and does not have his arguments thought out, he will recognize the truth when he hears your reply. But a Jewish heretic is someone who has learned Torah and nevertheless perverted its principles. No matter what Torah arguments you give him, he will not accept them. And on the contrary, whatever you tell him will cause him to become worse. Since he uses his Torah knowledge to bolster his position, the more knowledge he has, the worse he will become.