If someone eats non-Kosher food it causes him

A: Rabbenu Ha-Rav Tzvi Yehudah said: Emunah, since it is the basis for fulfilling the Mitzvot (Ha-Rav Meir Mazuz, Rosh Yeshiva of Kisei Rachamim, once mentioned that a Rav said that Yitzchak Avinu wanted to help Esav repent by teaching him Hilchot Shechitah based on Ba'al Ha-Turim on Berehit 27:3.But why would he teach Esav, who was wicked, this of all things?Rav Mazuz answers based on what is told about Ha-Rav Eleizer Man Shach, Rosh Yeshiva of Ponevitz.He was once asked by a group helping Ba'alei Teshuvah: Which Mitzvah should we begin with – Shabbat, Tefillin, etc.?Rav Shach said: Begin with Kashrut!"dulling of the heart" ["Timtum Ha-Lev"], i.e. dulling of one's spiritual sense.Vayikra 11:43.Yoma 31a.It is therefore clear why Yitzchak taught Esav the laws of Shechitah, so that he would eat Kosher, get back his proper spiritual sense, and repent.In the Parashah Sheet "Beit Ne'eman" #42.To the same question, Ha-Rav Yehudah Amital, Rosh Yeshiva of Har Etzion, said we should follow Hashem's actions!After the Jews left Egypt and began to complain, Hashem gave them 3 Mitzvot at Marah: Shabbat, understandable laws [Dinim] and Parah Adumah.Rashi on Shemot 15:25.Ha-Rav Amital therefore said that a Baal Teshuvah should begin with observing Shabbat, one Mitzvah which is dear to him [Dinim] and a Mitzvah which he does not understand, similar to Parah Adumah!Told to me by R' Dov Shachor from Yishuv Neriya).