Rabbi Eliezer says: In Nisan they were redeemed, and in Tishrei they are destined to be redeemed, as it is written, "Blow the horn at the new moon" (Psalms 81:4), and it is written, "And it shall come to pass on that day that a great horn shall be blown" (Isaiah 27:13). Rabbi Yehoshua says: In Nisan they were redeemed and in Nisan they are destined to be redeemed; what is the reason? "It is a night of watching unto the LORD," a night that has been guarded and ready since the six days of creation. And the other [understands]: a night guarded and protected from the harmful spirits. We learned there [in the Mishnah]: They must not give him fewer than four cups [of wine]. But how could the rabbis stand and institute a matter through which one might come to danger? For it has been taught: One should not eat in pairs nor drink in pairs. Rav Nachman bar Yitzchak said: Scripture says, "It is a night of watching unto the LORD" [a night guarded and protected from the harmful spirits].
Yalkut Shimoni on Torah 210:3
Yalkut Shimoni on Torah 210:3
רַבִּי אֱלִיעֶזֶר אוֹמֵר, בְּנִיסָן נִגְאֲלוּ, בְּתִשְׁרֵי עֲתִידִין לְהִגָּאֵל, דִּכְתִיב (תהלים פא, ד) "תִּקְעוּ בַחֹדֶשׁ שׁוֹפָר", וּכְתִיב "וְהָיָה בַּיּוֹם הַהוּא יִתָּקַע בְּשׁוֹפָר גָּדוֹל". רַבִּי יְהוֹשֻׁעַ אוֹמֵר, בְּנִיסָן נִגְאֲלוּ וּבְנִיסָן עֲבִידִין לְהִגָּאֵל, מַאי טַעְמָא, לֵיל שִׁמֻּרִים הוּא לַה', לַיְלָה הַמְּשֻׁמָּר וּבָא מִשֵּׁשֶׁת יְמֵי בְּרֵאשִׁית. וְאִידָךְ, לַיְלָה הַמְּשֻׁמָּר וּבָא מִן הַמַּזִּיקִין. תְּנַן הָתָם, לֹא יִפְחֲתוּ לוֹ מֵאַרְבַּע כּוֹסוֹת, וְהֵיכִי קַיְימֵי רַבָּנָן וּמְתַקְּנֵי מִילְתָּא דְּאָתֵי בָּהּ לְידֵי סַכָּנָה, וְהָתַנְיָא, לֹא יֹאכַל תְּרֵי וְלֹא יִשְׁתֶּה תְּרֵי אָמַר רַב נַחְמָן בַּר יִצְחָק, אָמַר קְרָא, לֵיל שִׁמֻּרִים הוּא לַה', לַיְלָה הַמְּשֻׁמָּר וּבָא מִן הַמַּזִּיקִין.