השרץ השרץ בכל נפשתיכם את תשקצו את” אלקיכם ‘ה אני כי :בם ונטמתם בהם תטמאו ולא (מד-מג יא) “קדשים והייתם והתקדשתם
The passuk “venitmeisem bam” is explained by Chazal (Yoma 39a): “Do not read it ונטמאתם but rather ונטמתם” to teach you that “aveirah clogs up the heart of a person.” And the Mesillas Yesharim writes (Ch. 11), that even though every aveirah clogs up the heart, eating forbidden foods does it much more “because they enter the person’s body literally, and become part of his flesh.”
Rav Chaim Palagi explains based on this why the Anshei Knesses Hagedolah established in Shemoneh Esreh that the brachah of Atah Chonen is right after Atah Kadosh. Because by avoiding forbidden foods a person fulfills the passuk והתקדשתם and he is saved from והייתם קדושים the timtum halev, and thus he merits wisdom, insight and knowledge.
Rav Chaim Kanievsky added an explanation for the words of the tefillah of Yom Kippur: “Atah chofes kol chadrei beten ubochen klayos valev,” and it means that Hakadosh Baruch Hu tests the purity of the kidneys and the heart that guide the way of a person, as Chazal say (Brachos 61a): “Kidneys advise, the heart understands,” by “chofes kol chadrei beten” – examining the chambers of the stomach, to ensure they were not sullied by forbidden foods.
Birchas Moadecha L’chaim Vol. II, Drush 21 for Shabbos Hagadol; Machzor Siach Sifsoseinu Yom Hakippurim p. 81
