It is stated, “When I celebrate the appointed Festival; I will judge [its theme] with fairness” (Tehillim 75:3). King Dovid was prompted to write these words because he recognized that our way is not that of the nations of the world, nor is our custom like theirs. For on their festive days they eat and drink to intoxication and go dancing in their public houses and commit other undesirable acts. But this is not the case with Israel, for although they also eat and drink and rejoice in the performance of the commandments, they are careful to spend half the day in prayer, expanding the service with special liturgies, after which they engage in study. All this is hinted at in the word “uprightly” [meisharim], as King Dovid said, “I will judge uprightly.” The mem [the numerical value of which is 40] of meisharim alludes to the forty days during which the Torah was given. And although Israel also rejoices on the Shabbos and Yom Tov, they do not neglect the three prayer services, morning, afternoon and evening. These are hinted at in the shi’en of meisharim [a shi’en is comprised of three vertical lines connected at the bottom]. And sometimes a shi’en is written with four heads [a four- headed shin appears on the side of the head tefillin]. This hints at the four prayers that are said on the festivals: morning, additional [mussaf], afternoon and evening. Moreover, we extend our prayers with additional poems and with the liturgical verses of the Krovetz [interspersed with the blessings of the Amidah on special occasions]. The word Krovetz itself is an acronym for the verse, Kol rinah viyshuah be’ohalei tzaddikim — “The voice of rejoicing and salvation in the tents of the righteous” (Tehillim 118:15). This is hinted at in the letters reish and yud of the word meisharim, which stand for rinah and yeshuah — “rejoicing and salvation.” The final mem of meisharim hints at the future redemption, which is alluded to in the phrase, lemarbei hamisrah — “for the increase of the realm” (Yeshayahu 9:6; the mem of lemarbei is uncharacteristically a final mem). This is to tell you that although we are filled with gladness and rejoicing on our festivals, nevertheless we pray for the promised redemption. For our happiness will only be complete when the Holy One Blessed is He rejoices with Tziyon and Yerushalayim.
It is stated in the Zohar (Parashas Emor, 94a) that when Israel first lauds the Holy One Blessed is He with songs of praise in their synagogues and study halls and afterwards come home to arrange their houses and tables in honor of Shabbos and Yom Tov, the angels proclaim, “Fortunate is the people whose lot is thus!” (Tehillim 144:15).
Therefore let not the recitation of the Krovetz seem unimportant in a person’s eyes. Rather let him recite them with joy, with concentration of the heart and with careful diction, because each of these liturgical hymns is filled with awesome esoteric allusions. Let them not seem burdensome to him, for they were composed with the assistance of angels from heaven who appeared to Rabbi Eliezer HaKalir. In fact he arranged them alphabetically, alef to tav and tav to alef, because that is how the angels sing and utter praise On High. The elders and the pious of the generation have passed on to me an oral tradition that if a person belittles the recitation of the Krovetz and downplays the obligation to say it, he will not live out his years, Heaven forbid. For all the unique individuals who composed these poems were leaders of the generation and men of great deeds, for whom numerous miracles were performed both in their lifetimes and after their deaths.
For example, we find the following incident recorded (Shalsheles HaKabbalah, 89a; Seder HaDoros 4830) regarding one leader of the generation by the name of Rabbi Shlomo Gevirol, z”l. He was a master of the esoteric tradition and also of grammar and composed a great number of liturgical poems. But the enemies of Israel were jealous of his vast wisdom, so one day an Ishmaelite lay in wait and murdered him, burying him in his garden beside a fig tree. From that time on this fig tree would always blossom before its time, producing giant and beautiful figs, which was a source of amazement to the entire town. Eventually word of the matter reached the king, who sent for the Ishmaelite and inquired from where he had learned the secret of causing fruit to ripen before its time. Out of his great fear the Ishmaelite was unable to respond, which was the hand of Providence. The king commanded that the man be tortured with harsh and bitter torments until at last he was compelled to confess that from the day that he murdered the Jew, Rabbi Shlomo Gevirol, the tree had begun producing fruit before its time. Upon hearing this the king ordered that the murderer be hung from that very tree.
The point to remember is that the entire congregation of Hashem is holy and the leaders of the generation were the ones who composed these poems. For this reason it is a good practice to take note of the name of the author of the liturgical or penitential poem one is reciting, as it is recorded in the acrostic. Pray that his merit should stand by you and that the recitation of his words of praise should be acceptable. For the author’s soul receives satisfaction when people recite his liturgical or penitential poems with proper concentration. This is especially the case on Shabbos and Yom Tov when the ascending souls bear Israel’s prayers On High and the Holy One Blessed is He hearkens to them. This is the reason that we remember the souls of deceased family members on Shabbos and Yom Tov. These are favorable times for pledging charity in their memory, mentioning their names and praying that they be bound up in the bond of life and it is a fitting custom to mention them and pray for them. It is especially important to mention the merit that the souls of one’s ancestors and Torah mentors deserve for having disseminated Torah among Israel and for establishing many disciples. But a person should not say that he is praying “in the merit of the charity that I vow to give for the remembering of their souls,” lest he delay in fulfilling his vow, Heaven forbid. For then the soul on whose behalf he pledged the donation will turn against him and become his accuser.
Thus did I find it written in the name of the Maharil, z”l (Minhagei Maharil, glosses on the laws of Yom Kippur). I have also heard a fitting explanation as to why the custom in Poland is to remember the souls of the deceased on the last day of Yom Tov. You must know that one of the ten miracles that occurred regularly in the Holy Temple was that three times a year the entire nation was able to enter it, on the festival of Matzos, the festival of Weeks [Shavuos] and the festival of Sukkos. And although the people were crowded together when they stood upright, when they prostrated themselves on the ground there was ample room for all (Avos 5:5), a situation that flew in the face of natural law. The explanation behind this miracle is as follows: On each festival the souls of Avraham, Yitzchak and Yaakov used to visit the heavenly Temple accompanied by the souls of all the righteous. At that time the earthly Temple would move aside and the heavenly Temple would descend to earth to take its place. And since the heavenly Temple was a spiritual edifice it was capable of holding all of Israel. And now that the Holy Temple has been destroyed, on account of our sins, we recall the souls of our holy ancestors on every festival so that their merits will stand by us and our offspring forever, Amein. — Based on the words of my teacher and mentor, Rabbi Yosef, z”l (Yesod Yosef, Chapter 87).
"כִּי אֶקַּח מוֹעֵד אֲנִי מֵישָׁרִים אֶשְׁפֹּט" (תְּהִלִּים עה, ג). דָּוִד הַמֶּלֶךְ עָלָיו הַשָּׁלוֹם אָמַר כֵּן, עֲבוּר שֶׁרָאָה שֶׁלֹּא דַּרְכֵּנוּ כְּדַרְכֵי אֻמּוֹת הָעוֹלָם, וְלֹא מִנְהָגֵנוּ כְּמִנְהָגָם — שֶׁבְּיוֹם חַגֵּיהֶם אוֹכְלִין וְשׁוֹתִין וּמִשְׁתַּכְּרִין וְעוֹסְקִים בִּמְחוֹלוֹת בְּבָתֵּי אֻשְׁפִּיזָאוֹת וּפוֹעֲלִין פְּעֻלּוֹת לֹא טוֹבוֹת. מַה שֶּׁאֵין כֵּן יִשְׂרָאֵל: אַף עַל פִּי שֶׁאוֹכְלִין, שׁוֹתִין וּשְׂמֵחִין בְּשִׂמְחָה שֶׁל מִצְוָה — הֵם עוֹסְקִים חֲצִי הַיּוֹם בִּתְפִלָּה וּמַאֲרִיכִין בְּפִיּוּטִים, וְאַחַר כָּךְ לוֹמְדִין תּוֹרָה. וְזֶהוּ נִרְמָז בְּתֵבַת 'מֵישָׁרִים'. לָכֵן דָּוִד אָמַר: אֲנִי מֵישָׁרִים אֶשְׁפֹּט. מֵ"ם שֶׁל 'מֵישָׁרִים' רוֹמֵז לְאַרְבָּעִים יוֹם שֶׁנִּתְּנָה הַתּוֹרָה. וְאַף שֶׁיִּשְׂרָאֵל עוֹסְקִים גַּם כֵּן בְּשִׂמְחַת שַׁבָּת וּבְשִׂמְחַת יָמִים טוֹבִים — אֵינָם מְבַטְּלִין שָׁלשׁ תְּפִלּוֹת: שַׁחֲרִית, מִנְחָה, עַרְבִית. וַעֲלֵיהֶם רוֹמֵז אוֹת שִׁי"ן שֶׁל 'מֵישָׁרִים'. וְלִפְעָמִים כּוֹתְבִין הַשִּׁי"ן בְּאַרְבָּעָה רָאשִׁין, כָּזֶה: [
] שֶׁהֵן רֶמֶז לְאַרְבַּע תְּפִלּוֹת: שַׁחֲרִית, מוּסָף, מִנְחָה, עַרְבִית. וְלֹא עוֹד, אֶלָּא שֶׁאָנוּ מוֹסִיפִים פִּיּוּטִים וְשִׁירוֹת שֶׁל קְרוֹבַ"ץ, שֶׁהֵן רָאשֵׁי תֵּבוֹת קוֹל רִנָּה וִישׁוּעָה בְּאָהֳלֵי צַדִּיקִים. וְזֶהוּ נִרְמָז בְּאוֹתִיּוֹת רֵי"שׁ וְיוּ"ד שֶׁל מֵישָׁרִים, שֶׁהוּא רִנָּה וִישׁוּעָה, וּמֵ"ם סְתוּמָה שֶׁל מֵישָׁרִים מְרַמֶּזֶת עַל הַגְּאֻלָּה הָעֲתִידָה, שֶׁנִּרְמָז בְּמֵ"ם סְתוּמָה שֶׁל "לְםַרְבֵּה הַמִּשְׂרָה" (יְשַׁעְיָה ט, ו). לוֹמַר לְךָ, שֶׁאֲפִלּוּ שֶׁאָנוּ שְׂמֵחִים וְשָׂשִׂים בְּחַגֵּינוּ — אַף עַל פִּי כֵן אָנוּ מִתְפַּלְּלִים עַל הַגְּאֻלָּה הָעֲתִידָה, שֶׁיִּהְיֶה שִׂמְחָה שְׁלֵמָה, כְּשֶׁיְּשַׂמַּח הַקָּדוֹשׁ בָּרוּךְ הוּא אֶת צִיּוֹן וִירוּשָׁלַיִם.
It is stated, “When I celebrate the appointed Festival; I will judge [its theme] with fairness” (Tehillim 75:3). King Dovid was prompted to write these words because he recognized that our way is not that of the nations of the world, nor is our custom like theirs. For on their festive days they eat and drink to intoxication and go dancing in their public houses and commit other undesirable acts. But this is not the case with Israel, for although they also eat and drink and rejoice in the performance of the commandments, they are careful to spend half the day in prayer, expanding the service with special liturgies, after which they engage in study. All this is hinted at in the word “uprightly” [meisharim], as King Dovid said, “I will judge uprightly.” The mem [the numerical value of which is 40] of meisharim alludes to the forty days during which the Torah was given. And although Israel also rejoices on the Shabbos and Yom Tov, they do not neglect the three prayer services, morning, afternoon and evening. These are hinted at in the shi’en of meisharim [a shi’en is comprised of three vertical lines connected at the bottom]. And sometimes a shi’en is written with four heads [a four- headed shin appears on the side of the head tefillin]. This hints at the four prayers that are said on the festivals: morning, additional [mussaf], afternoon and evening. Moreover, we extend our prayers with additional poems and with the liturgical verses of the Krovetz [interspersed with the blessings of the Amidah on special occasions]. The word Krovetz itself is an acronym for the verse, Kol rinah viyshuah be’ohalei tzaddikim — “The voice of rejoicing and salvation in the tents of the righteous” (Tehillim 118:15). This is hinted at in the letters reish and yud of the word meisharim, which stand for rinah and yeshuah — “rejoicing and salvation.” The final mem of meisharim hints at the future redemption, which is alluded to in the phrase, lemarbei hamisrah — “for the increase of the realm” (Yeshayahu 9:6; the mem of lemarbei is uncharacteristically a final mem). This is to tell you that although we are filled with gladness and rejoicing on our festivals, nevertheless we pray for the promised redemption. For our happiness will only be complete when the Holy One Blessed is He rejoices with Tziyon and Yerushalayim.
וְאִיתָא בַּזֹּהַר פָּרָשַׁת אֱמֹר: כְּשֶׁיִּשְׂרָאֵל מְשַׁבְּחִין תְּחִלָּה לְהַקָּדוֹשׁ בָּרוּךְ הוּא בְּתִשְׁבָּחוֹת וּבִזְמִירוֹת בְּבָתֵּי כְּנֵסִיּוֹת וּבְבָתֵּי מִדְרָשׁוֹת, וְאַחַר כָּךְ בָּאִים לְבֵיתָם וּמְסַדְּרִים בָּתֵּיהֶם וְשֻׁלְחָן שֶׁלָּהֶם, וְאוֹמְרִים שֶׁהַכֹּל לִכְבוֹד שַׁבָּת וְלִכְבוֹד יוֹם טוֹב — אָז פּוֹתְחִין מַלְאֲכֵי הַשָּׁרֵת וְאוֹמְרִים: אַשְׁרֵי הָעָם שֶׁכָּכָה לוֹ!
It is stated in the Zohar (Parashas Emor, 94a) that when Israel first lauds the Holy One Blessed is He with songs of praise in their synagogues and study halls and afterwards come home to arrange their houses and tables in honor of Shabbos and Yom Tov, the angels proclaim, “Fortunate is the people whose lot is thus!” (Tehillim 144:15).
עַל כֵּן לֹא יִהְיֶה קַל בְּעֵינֶיךָ אֲמִירַת פִּיּוּטִים שֶׁל קְרוֹבַ"ץ. וְחִיּוּב עַל כָּל אָדָם לוֹמַר הַפִּיּוּטִים בְּשִׂמְחָה וּבְכַוָּנַת הַלֵּב בְּשָׂפָה בְּרוּרָה, כִּי בְּכָל פִּיּוּט וּפִיּוּט יֵשׁ סוֹדוֹת נִפְלָאִין. וְלֹא יִהְיוּ הַפִּיּוּטִין דּוֹמִין עָלֶיךָ כְּמַשָּׂא, כִּי הַפִּיּוּטִים נִתְחַבְּרוּ עַל פִּי עֲצַת מַלְאֲכֵי מַעְלָה, שֶׁנִּגְלוּ לְרַבִּי אֶלְעָזָר הַקַּלִּירִי, שֶׁסִּדֵּר הַפִּיּוּטִים עַל פִּי א, ב, ג, ד וְעַל פִּי תַּשְׁרָ"ק, כִּי כֵן מְזַמְּרִין וּמְשַׁבְּחִין לְמַעְלָה. וְקַבָּלָה בְּיָדִי מִפִּי זְקֵנִים וּמִפִּי חֲסִידִים: מִי שֶׁמֵּקֵל בַּאֲמִירַת קְרוֹבַ"ץ וְאוֹמֵר שֶׁאֵינוֹ חִיּוּב כָּל כָּךְ לְאָמְרָם — אֵינוֹ מַאֲרִיך יָמִים, חַס וְשָׁלוֹם, כִּי כָּל הַיְחִידִים שֶׁחִבְּרוּ הַפִּיּוּטִים, הָיוּ גְדוֹלֵי הַדּוֹר וְאַנְשֵׁי מַעֲשֶׂה, אֲשֶׁר נַעֲשָׂה לָהֶם כַּמָּה נִסִּים בְּחַיֵּיהֶן וּבְמִיתָתָן.
Therefore let not the recitation of the Krovetz seem unimportant in a person’s eyes. Rather let him recite them with joy, with concentration of the heart and with careful diction, because each of these liturgical hymns is filled with awesome esoteric allusions. Let them not seem burdensome to him, for they were composed with the assistance of angels from heaven who appeared to Rabbi Eliezer HaKalir. In fact he arranged them alphabetically, alef to tav and tav to alef, because that is how the angels sing and utter praise On High. The elders and the pious of the generation have passed on to me an oral tradition that if a person belittles the recitation of the Krovetz and downplays the obligation to say it, he will not live out his years, Heaven forbid. For all the unique individuals who composed these poems were leaders of the generation and men of great deeds, for whom numerous miracles were performed both in their lifetimes and after their deaths.
וְכִדְמָצִינוּ בִּגְדוֹל הַדּוֹר אֶחָד, הַנִּקְרָא רַבִּי שְׁלֹמֹה גְּבִירוֹל, זִכְרוֹנוֹ לִבְרָכָה, שֶׁהָיָה בָּקִי בְּחָכְמַת הַקַּבָּלָה וּבְדִקְדוּק וְחִבֵּר הַרְבֵּה פִּיּוּטִים, מֵרֹב חָכְמָתוֹ נִתְקַנְּאוּ בּוֹ שׂוֹנְאֵי יִשְׂרָאֵל, וְאָרַב עָלָיו יִשְׁמָעֵאל אֶחָד וַהֲרָגוֹ וּקְבָרוֹ בַּגַּן שֶׁלּוֹ אֵצֶל אִילָן תְּאֵנָה, וְהַתְּאֵנָה חָנְטָה פַּגֶּיהָ קֹדֶם זְמַנָּהּ וְעָשְׂתָה פֵּרוֹת תְּאֵנִים גְּדוֹלִים וְיָפִים מְאֹד. וַיִּתְמְהוּ כָּל יוֹשְׁבֵי הָעִיר, וְהַדָּבָר בָּא אֶל מֶלֶךְ הַיִּשְׁמְעֵאלִים, וַיַּרְא הַמֶּלֶךְ הַפֵּרוֹת, וַיִּתְמַהּ. וַיִּשְׁלַח הַמֶּלֶךְ אַחַר הַיִּשְׁמְעֵאלִי הַנִּזְכָּר לְעֵיל, וְשָׁאַל אוֹתוֹ אֵיךְ הִתְחַכֵּם לַעֲשׂוֹת פְּעֻלָּה לְבַשֵּׁל הַפֵּרוֹת קֹדֶם זְמַנָּם. וּמֵרֹב פַּחַד לֹא יָכוֹל הַיִּשְׁמָעֵאל לְהָשִׁיב אֶל הַמֶּלֶךְ, כִּי הָיְתָה הַסִּבָּה מֵאֵת ה'. וְהָיָה מְצַוֶּה הַמֶּלֶךְ לְיַסֵּר אוֹתוֹ בְּיִסּוּרִים קָשִׁים וּמָרִים, עַד שֶׁהֻכְרַח הַיִּשְׁמְעֵאלִי לְהוֹדוֹת. וְהוֹדָה, שֶׁמֵּאוֹתוֹ הַיּוֹם שֶׁהָרַג אֶת הַיְּהוּדִי רַבִּי שְׁלֹמֹה גְּבִירוֹל, הִתְחִיל הָאִילָן לַעֲשׂוֹת פֵּרוֹת קֹדֶם זְמַנּוֹ, וְצִוָּה הַמֶּלֶךְ לִתְלוֹת אֶת הַיִּשְׁמְעֵאלִי הָרוֹצֵחַ עַל אוֹתוֹ הָאִילָן.
For example, we find the following incident recorded (Shalsheles HaKabbalah, 89a; Seder HaDoros 4830) regarding one leader of the generation by the name of Rabbi Shlomo Gevirol, z”l. He was a master of the esoteric tradition and also of grammar and composed a great number of liturgical poems. But the enemies of Israel were jealous of his vast wisdom, so one day an Ishmaelite lay in wait and murdered him, burying him in his garden beside a fig tree. From that time on this fig tree would always blossom before its time, producing giant and beautiful figs, which was a source of amazement to the entire town. Eventually word of the matter reached the king, who sent for the Ishmaelite and inquired from where he had learned the secret of causing fruit to ripen before its time. Out of his great fear the Ishmaelite was unable to respond, which was the hand of Providence. The king commanded that the man be tortured with harsh and bitter torments until at last he was compelled to confess that from the day that he murdered the Jew, Rabbi Shlomo Gevirol, the tree had begun producing fruit before its time. Upon hearing this the king ordered that the murderer be hung from that very tree.
הַכְּלָל הָעוֹלֶה — כִּי כָּל הָעֵדָה, עֲדַת ה', כֻּלָּם קְדוֹשִׁים וּגְדוֹלֵי הַדּוֹר תִּקְּנוּ הַפִּיּוּטִים. וְלָכֵן טוֹב לְכַוֵּן אֶל הָרֶמֶז שֵׁם הַמְחַבֵּר הַפִּיּוּט אוֹ הַמְחַבֵּר אֶת הַסְּלִיחָה, וִיכַוֵּן שֶׁיַּעֲמֹד זְכוּתוֹ, שֶׁיַּעֲלֶה לְרָצוֹן אֲמִירַת שֶׁבַח הַמְחַבֵּר, כִּי יֵשׁ נַחַת רוּחַ לְאוֹתוֹ הַמְחַבֵּר כְּשֶׁאוֹמְרִים פִּיּוּטוֹ אוֹ סְלִיחָה שֶׁלּוֹ בְּכַוָּנָה, וּבִפְרָט בְּשַׁבָּת וְיוֹם טוֹב, שֶׁאָז הַנְּשָׁמוֹת עוֹלִין עִם תְּפִלָּתָן שֶׁל יִשְׂרָאֵל, וְהַקָּדוֹשׁ בָּרוּךְ הוּא מַאֲזִין תְּפִלָּתָן שֶׁל יִשְׂרָאֵל. וְזֶה הַטַּעַם שֶׁל הַזְכָּרַת נְשָׁמוֹת בְּשַׁבָּתוֹת וְיָמִים טוֹבִים, כִּי הוּא עֵת רָצוֹן לִנְדֹּר בְּשַׁבָּת וְיוֹם טוֹב לִצְדָקָה בְּעַד הַזְכָּרַת נְשָׁמוֹת וּלְהַזְכִּירָם וּלְהִתְפַּלֵּל עֲלֵיהֶם, שֶׁיִּהְיוּ נַפְשׁוֹתָן צְרוֹרוּת בִּצְרוֹר הַחַיִּים. וּמִנְהָג יָפֶה הוּא לְהַזְכִּיר נְשָׁמוֹת וּלְהִתְפַּלֵּל עֲלֵיהֶם, וּבִפְרָט שֶׁצָּרִיךְ לְהַזְכִּיר נִשְׁמוֹת אֲבוֹתָיו וְרַבּוֹתָיו בַּעֲבוּר שֶׁהִרְבִּיצוּ תּוֹרָה בְּיִשְׂרָאֵל וְהֶעֱמִידוּ תַּלְמִידִים הַרְבֵּה. וְלֹא יֹאמַר: בַּעֲבוּר שֶׁאֲנִי נוֹדֵר צְדָקָה בְּעַד הַזְכָּרַת נִשְׁמָתָם, שֶׁמָּא, חַס וְשָׁלוֹם, יְעַכֵּב בְּתַשְׁלוּמֵי הַנֶּדֶר שֶׁנָּדַר, וְאָז תֵּהָפֵך אֵלָיו אוֹתָהּ הַנְּשָׁמָה, שֶׁנָּדַר צְדָקָה בַּעֲבוּרָהּ לִמְקַטְרֵג.
The point to remember is that the entire congregation of Hashem is holy and the leaders of the generation were the ones who composed these poems. For this reason it is a good practice to take note of the name of the author of the liturgical or penitential poem one is reciting, as it is recorded in the acrostic. Pray that his merit should stand by you and that the recitation of his words of praise should be acceptable. For the author’s soul receives satisfaction when people recite his liturgical or penitential poems with proper concentration. This is especially the case on Shabbos and Yom Tov when the ascending souls bear Israel’s prayers On High and the Holy One Blessed is He hearkens to them. This is the reason that we remember the souls of deceased family members on Shabbos and Yom Tov. These are favorable times for pledging charity in their memory, mentioning their names and praying that they be bound up in the bond of life and it is a fitting custom to mention them and pray for them. It is especially important to mention the merit that the souls of one’s ancestors and Torah mentors deserve for having disseminated Torah among Israel and for establishing many disciples. But a person should not say that he is praying “in the merit of the charity that I vow to give for the remembering of their souls,” lest he delay in fulfilling his vow, Heaven forbid. For then the soul on whose behalf he pledged the donation will turn against him and become his accuser.
מָצָאתִי כָּתוּב בְּשֵׁם מַהֲרִי"ל, זִכְרוֹנוֹ לִבְרָכָה, וְשָׁמַעְתִּי טַעַם הָגוּן, לָמָּה מַזְכִּירִין נְשָׁמוֹת בִּמְדִינוֹת פּוֹלִין בְּאַחֲרוֹן שֶׁל יָמִים טוֹבִים: דַּע, כִּי אַחַת מֵעֲשָׂרָה נִסִּים שֶׁהָיוּ בַּמִּקְדָּשׁ הוּא, שֶׁכָּל יִשְׂרָאֵל הָיוּ נִכְנָסִים לְבֵית הַמִּקְדָּשׁ שָׁלשׁ פְּעָמִים בַּשָּׁנָה: בְּחַג הַמַּצּוֹת וּבְחַג הַשָּׁבוּעוֹת וּבְחַג הַסֻּכּוֹת. וְהָיוּ עוֹמְדִים צְפוּפִים וּמִשְׁתַּחֲוִים רְוָחִים. וְזֶהוּ הָיָה נֶגֶד הַטֶּבַע. וְהָעִנְיָן כָּךְ — כִּי כָּל רֶגֶל וְרֶגֶל הָיוּ בָּאִים נִשְׁמַת אַבְרָהָם, יִצְחָק וְיַעֲקֹב לְבֵית הַמִּקְדָּשׁ שֶׁל מַעְלָה עִם כָּל נִשְׁמוֹת הַצַּדִּיקִים, וְהַמִּקְדָּשׁ שֶׁל מַטָּה הָיָה מִסְתַּלֵּק, וְהָיָה הַבֵּית הַמִּקְדָּשׁ שֶׁל מַעְלָה יוֹרֵד לְמַטָּה. וּמִקְדָּשׁ שֶׁל מַעְלָה הוּא רוּחָנִי, וְלָכֵן הָיָה יָכוֹל לְקַבֵּל כָּל כְּלַל יִשְׂרָאֵל. וְלָכֵן עַכְשָׁו, שֶׁחָרַב הַבַּיִת בַּעֲווֹנֵינוּ, צְרִיכִין אָנוּ לְהַזְכִּיר נִשְׁמוֹת אֲבוֹתֵינוּ הַקְּדוֹשִׁים בְּכָל רֶגֶל וְרֶגֶל, כְּדֵי שֶׁיִּהְיֶה זְכוּתָם עוֹמֶדֶת לָנוּ וּלְזַרְעֵנוּ עַד עוֹלָם. אָמֵן.
Thus did I find it written in the name of the Maharil, z”l (Minhagei Maharil, glosses on the laws of Yom Kippur). I have also heard a fitting explanation as to why the custom in Poland is to remember the souls of the deceased on the last day of Yom Tov. You must know that one of the ten miracles that occurred regularly in the Holy Temple was that three times a year the entire nation was able to enter it, on the festival of Matzos, the festival of Weeks [Shavuos] and the festival of Sukkos. And although the people were crowded together when they stood upright, when they prostrated themselves on the ground there was ample room for all (Avos 5:5), a situation that flew in the face of natural law. The explanation behind this miracle is as follows: On each festival the souls of Avraham, Yitzchak and Yaakov used to visit the heavenly Temple accompanied by the souls of all the righteous. At that time the earthly Temple would move aside and the heavenly Temple would descend to earth to take its place. And since the heavenly Temple was a spiritual edifice it was capable of holding all of Israel. And now that the Holy Temple has been destroyed, on account of our sins, we recall the souls of our holy ancestors on every festival so that their merits will stand by us and our offspring forever, Amein. — Based on the words of my teacher and mentor, Rabbi Yosef, z”l (Yesod Yosef, Chapter 87).