וְלֹא תְטַמְאוּ אֶת־נַפְשֹתֵיכֶם ...And you should not contaminate your souls...(Vayikra 11:44) Following this verse, the Torah says: כִּי אֲנִּי ה‘ הַמַַּֽעֲלֶה אֶתְכֶם מֵאֶרֶץ מִּצְרַיִּם - Because I am Hashem who brings you up from the land of Egypt...
What is the connection between Yetzias Mitzrayim and the mitzva to keep our souls pure? The Sefas Emes (Shmini, 5637) explains that the gift of geula to each Jew was his pure soul. The soul, says the Sefas Emes, is the source of רצון - the will and desire. And when the soul is pure, then we have the will and desire to bring joy to our Father in Shamayim through learning Torah and fulfilling His mitzvos. Yetzias Mitzrayim is what gave us that pure soul. And each year - during Pesach - we relive Yetzias Mitzrayim, and Hashem once again grants us this precious gift - the pure soul.
Now, after receiving this gift, we are instructed not to defile it: וְלֹא תְטַמְאוּ אֶת־נַפְשֹתֵיכֶם - And you should not contaminate your souls...(Vayikra 11:44) That is connection between Yetzias Mitzrayim and the mitzva to keep our souls pure.
Practically speaking, what should a person do (or not do) to protect the purity of his soul? First of all, by eating kosher food - since that’s the context of the above verse. But in addition to that, the Sefas Emes points out that king Shlomo taught us in Mishlei: שֹמֵר פִּיו וּלשוֹנוֹ שֹמֵר מִּצָּרוֹת נַפְשוֹ. - “One who guards his mouth and tongue guards his soul from troubles.” [Mishlei 21:23] Therefore, if we’ll stay away from non-kosher food and non-kosher speech, we’ll protect the purity of our soul - preserving that precious gift - the desire to do Hashem’s will.
