תפארת שלמה, על הזמנים ומועדים, רמזי פסח פ׳
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שמות רבה כ״ב:ג׳
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שמות רבה כ״ג:ט״ו
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פרק שירה, הקדמה א׳
Rabbi Eliezer said: Anyone who involves himself with Perek Shirah in this world, merits saying it in the World-to-Come, as it says, “Then Moshe will sing”; it does not say “sang,” but “will sing” in the World-to-Come.