It should be explained why only the plague of the firstborn is mentioned in the Hallel prayer, and not the other plagues. Similarly, an explanation is needed for why only the plague of the firstborn is mentioned in the piyyut "Dayenu."

In the Talmud (Berakhot 12a), it is stated: "Rabbah bar Hana Sav'a said in the name of Rav, anyone who does not say 'Emet VeYatziv' in the morning and 'Emet VeEmunah' in the evening has not fulfilled his obligation, as it says (Psalms 92:3), 'To declare Your kindness in the morning and Your faithfulness at night'." Rashi explains: "And the blessing of 'Emet VeYatziv' is all about the kindness He did with our ancestors, for He took them out of Egypt, split the sea for them, and brought them through."

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