Rabbi Joshua ben Levi taught that we read the Megillah twice as a
reflection of the verse in Psalms (22:3), “O my G‑d, I call in the day
time . . . and in the night I am not silent.” This verse is part of a
chapter which the sages of the Talmud (Yoma 29a) associate with Queen
As the threat of genocide loomed, the distressed Jews of the Purim
story cried out to G‑d during the night and day. Thus, we recall His
kindness on the eve of Purim and then again the following day.2
Rabbi Chelbo would quote Ula of Biri, who associated this practice
with the verse in Psalms (30:13), “So that my soul will sing praises
to You and not be silent . . . I will thank You forever.“
Reading the Megillah twice is thus an expression of thanksgiving to
G‑d, as well as a testament to His everlasting kindness.
Eicha is read at night as it says in the passuk Eicha 1:1:
בָּכ֨וֹ תִבְכֶּ֜ה בַּלַּ֗יְלָה - Bitterly she weeps in the night...
Rashi (ibid) cites three explanations:
בַּלַּיְלָה. שֶׁהַמִּקְדָּשׁ נִשְׂרַף בַּלַּיְלָה, דְּאָמַר מַר "לְעֵת
עֶרֶב הִצִּיתוּ בוֹ אֶת הָאוּר". דָּבָר אַחֵר: "בַּלַיְלָה", לַיְלָה
שֶׁל בְּכִיַּת מְרַגְּלִים בְּתִשְׁעָה בְאָב גָּרְמָה לָהֶם. דָּבָר
אַחֵר: "בַּלַּיְלָה", שֶׁכָּל הַבּוֹכֶה בַלַּיְלָה, הַשּׁוֹמֵעַ קוֹלוֹ
In the night. For the Beis Hamikdosh was burned at night, as the
[Midrash] says, “at the time of evening they set it on fire.
Another explanation of “in the night,” [is that] the night of the
weeping of the spies on the ninth of Av caused it to happen to them.
Another explanation of “in the night,” is that whoever weeps at night,
the one who hears his voice weeps along with him.