There is an additional aspect in the matter of forbidden foods, for which reason they are called issur (“bound” and attached):

וְעוֹד זֹאת בְּמַאֲכָלוֹת אֲסוּרוֹת, שֶׁלְּכָךְ נִקְרָאִים בְּשֵׁם "אִיסּוּר",

Even if one ate a forbidden food unwittingly and his intention in eating was for the sake of heaven, i.e., in order to serve G-d with the energy derived from it;

מִפְּנֵי שֶׁאַף מִי שֶׁאָכַל מַאֲכַל אִיסּוּר בְּלֹא הוֹדַע – לְשֵׁם שָׁמַיִם, לַעֲבוֹד ה' בְּכֹחַ אֲכִילָה הַהִיא,

(Had the food been permitted, the very act of eating for the sake of heaven would suffice to extract the good from the evil of the food’s vitality, as explained above. In this instance, however, forbidden food was eaten for the sake of heaven.)

moreover, even if he actually carried out his intention, having studied and prayed with the energy derived from that food;

וְגַם פָּעַל וְעָשָׂה כֵּן, וְקָרָא וְהִתְפַּלֵּל בְּכֹחַ אֲכִילָה הַהִיא,

(Again, had the food been permitted and the person studied and prayed with the energy provided by the food, the energy would be elevated to Sanctity. But because the food was forbidden—)

the vitality contained in it does not ascend or become clothed in the words of Torah and prayer that he studies and prays with the energy of that food, as is the case with permitted foods,

אֵין הַחַיּוּת שֶׁבָּהּ עוֹלָה וּמִתְלַבֶּשֶׁת בְּתֵיבוֹת הַתּוֹרָה וְהַתְּפִלָּה כְּמוֹ הַהֶיתֵּר,

because it is held captive in the power of the sitra achara of the three unclean kelipot which do not permit the energy of the food to be elevated to Sanctity.

מִפְּנֵי אִיסּוּרָהּ בִּידֵי הַסִּטְרָא אָחֳרָא מִשָּׁלֹשׁ קְלִיפּוֹת הַטְּמֵאוֹת.

This is so even if it is forbidden by reason of a Rabbinic prohibition, for “the words i.e., the prohibitions of the Scribes are even more stringent than the words of the Torah….”1

וַאֲפִילוּ הוּא אִיסּוּר דְּרַבָּנָן, שֶׁחֲמוּרִים דִּבְרֵי סוֹפְרִים יוֹתֵר מִדִּבְרֵי תוֹרָה כוּ'.

Therefore, the yetzer hara (evil impulse) and the force that lusts after forbidden things is also “one of the non-Jewish demons,”2 which is the yetzer hara of the nations, whose souls are derived from the three unclean kelipot.

וְלָכֵן, גַּם הַיֵּצֶר הָרָע וְכֹחַ הַמִּתְאַוֶּה לִדְבָרִים הָאֲסוּרִים, הוּא שֵׁד מִשֵּׁדִין נוּכְרָאִין, שֶׁהוּא יֵצֶר הָרָע שֶׁל אוּמּוֹת הָעוֹלָם, שֶׁנַּפְשׁוֹתֵיהֶם מִשָּׁלֹשׁ קְלִיפּוֹת הַטְּמֵאוֹת.

They therefore lust after forbidden matters, since the forbidden matters, too, derive their energy from the three unclean kelipot.

On the other hand, the evil impulse and the craving force after permissible things even when done solely to satisfy one’s craving, in which case, as mentioned earlier, even the permissible matter descends into the utter evil of the three unclean kelipot; still, it is “one of the Jewish demons”2; it is, as it were, a Jewish evil impulse, for it (the vitality of a permitted thing) can be reverted to holiness, as was explained above.3

מַה שֶּׁאֵין כֵּן הַיֵּצֶר הָרָע וְכֹחַ הַמִּתְאַוֶּה לִדְבָרִים הַמּוּתָּרִים לְמַלֹּאת תַּאֲוָתוֹ, הוּא שֵׁד מִשֵּׁדִין יְהוּדָאִין, לְפִי שֶׁיָּכוֹל לַחֲזוֹר לִקְדוּשָּׁה כְּדִלְעֵיל.

Since the food itself is permissible, therefore, though it was eaten to satisfy bodily desire, it can still be elevated to holiness (when the person returns to the study of Torah and the service of G-d). The yetzer hara for forbidden matters, however, is intrinsically un-Jewish, i.e., essentially foreign to the Jew’s character. As explained elsewhere, one acquires this “foreign” yetzer hara by immersing himself in “permitted” pleasures. These so coarsen him that he begins to lust after prohibited matters as well—a desire totally unnatural for the Jew.

Although the vitality of permitted foods eaten out of bodily desire can revert to holiness through the person’s repentance, nevertheless, before it has reverted to holiness, it is sitra achara and kelipah,

אַךְ מִכָּל מָקוֹם, קוֹדֶם שֶׁחָזַר לִקְדוּשָּׁה, הוּא סִטְרָא אָחֳרָא וּקְלִיפָּה.

and even afterward (after the person repented and elevated the energy of the food to holiness), a trace of it remains attached to the person’s body,

וְגַם אַחַר כָּךְ, הָרְשִׁימוּ מִמֶּנּוּ נִשְׁאָר דָּבוּק בַּגּוּף,

since each item of food and drink that one ingests immediately becomes blood and flesh of his flesh.

לִהְיוֹת כִּי מִכָּל מַאֲכָל וּמַשְׁקֶה נַעֲשָׂה תֵּיכֶף דָּם וּבָשָׂר מִבְּשָׂרוֹ.

Since the food which became his flesh and blood was evil at the time of consumption—having been eaten for the sake of bodily pleasure—a trace of the kelipah remains in the body even after the person has repented and elevated the vitality of the food to holiness.

That is why the body must undergo the “Purgatory of the Grave” (a specific punishment for the body4) in order to cleanse it and purify it of the uncleanness which it had received from the enjoyment of mundane things and pleasures, which are from the impurity of the kelipat nogah and of the “Jewish demons” (i.e., the “Jewish yetzer hara” which desires permitted matters);

וְלָכֵן צָרִיךְ הַגּוּף לְחִיבּוּט הַקֶּבֶר, לְנַקּוֹתוֹ וּלְטַהֲרוֹ מִטּוּמְאָתוֹ שֶׁקִּיבֵּל בַּהֲנָאַת עוֹלָם הַזֶּה וְתַעֲנוּגָיו מִטּוּמְאַת קְלִיפַּת נוֹגַהּ וְשֵׁדִין יְהוּדָאִין.

unless one had never derived enjoyment from this world all his life (i.e., either he actually derived no enjoyment, or his enjoyment was not of this world, since all his actions were completely for the sake of mitzvot and holiness),

אֶלָּא אִם כֵּן מִי שֶׁלֹּא נֶהֱנָה מֵעוֹלָם הַזֶּה כָּל יָמָיו

as was the case with Rabbeinu Hakadosh (Rabbi Judah the Prince, who said at the time of his demise that he had had no enjoyment of this world even to the extent of his “small finger”).

כְּרַבֵּינוּ הַקָּדוֹשׁ.

He who never derived pleasure from this world all his life need not undergo the “Purgatory of the Grave.” However, anyone who has not attained this level must undergo this punishment to purify his body of the uncleanness received from the enjoyment of mundane pleasures.