Musar su Salmi 137:1

In the Zohar on Parashat Terumah [it is taught]: 'One who luxuriates at his table and delights in those foods ought to call to mind and to feel concern for the holiness of the Holy Land and for the Temple of the King that has been destroyed. In consideration of the sadness that one feels at one's table--in the midst of the joy and celebration [lit. drinking] there--the Holy Blessed One accounts it to one as if one has rebuilt His House and rebuilt all the ruins of the Temple. Happy is one's portion!' (Zohar 2:157:2). Therefore it is customary to recite the Psalm 'By the waters of Babylon' (Psalms 137) before Grace after Meals, particularly since the table corresponds to the (Temple) altar, while, through our many sins, the altar itself is no longer. One should call to mind [the teaching], 'Woe to the children who have been banished from their Father's table' (Talmud Berachot 3a). The banishment from the Table (shulchan, sh.l.h.n) was caused by the power of the Snake (lenachash, l.n.h.sh), as is taught in the Zohar [about the word] Eichah ('.y.kh.h, 'Alas;' the name of the Book of Lamentations): 'I shall set enmity' (Eivah, '.y.b.h) (Genesis 3:15), an anagram for א׳יכה י׳שבה ב׳דד ה׳עיר 'Alas, the city sits solitary' ('.y.b.h) (Lamentations 1:1). On Shabbat and Festivals one recites the Psalm 'When the Name restores the fortunes of Zion' (Psalms 126).

The Levites' cities absorbed those forced to go into exile because of their having committed involuntary manslaughter. When disaster struck the nation, the Levites too were sent into exile as we know from Psalm 137,3 which tells of the Levites being asked to sing the songs they used to sing in Zion. They responded by refusing, claiming they could not possibly do so on foreign soil. Our sages (Midrash Tehillim 137,5) say that they amputated the tops of their fingers so as to be unable to play their instruments. Israel without a rebuilt Temple is compared to כאדם עברו ברית, "just as Adam who had violated the covenant with G–d," in the words of Hoseah 6,7. Midrash Eichah Rabbah elaborates on this, Rabbi Abahu saying that G–d describes how he had placed Adam into Gan Eden, commanded him a single commandment, which he transgressed. G–d consequently punished him with expulsion and personally elegized him with the word איכ-ה, Ayekkoh, (Genesis 3,9), which can be read as Eychah, an expression of mourning as in Lamentations, and also as used by Moses in Deut. 1,12 in the same sense, until He was able to bring the Jewish people into the Holy Land. Jeremiah 2,7 describes this in the words ואביא אתכם אל ארץ הכרמל לאכול את פריה. "I have brought you to the land of the Carmel to eat its fruit." Proof that G–d commanded Israel to observe commandments in the Holy Land is derived from Numbers 34,2: "Command the children of Israel, say to them…when you enter the land of Canaan, etc." Israel transgressed these commandments as described in Daniel 9, 9-11. Daniel includes the whole people as having violated G–d's teachings, as a result of which the curses in the Torah were poured out over them. Our exile, too, was a result of such conduct as is stated in Hoseah 9,9: "I will expel them from My House." The expulsion was not only to a country adjoining their homeland, but also to far off places as is indicated by Jeremiah 15,1: שלח מעל פני ויצאו, "Dismiss them from My Presence; let them go forth!" In His elegy, G–d refers to the lonely and isolated situation Zion finds itself in as a result; cf. Lamentations 1,1. Thus the introduction of Midrash Eicha.