סימן יד סעיף ה
בַּשַׁבָּת וּבְיוֹם טוֹב אֵין אוֹמְרִים מִזְמוֹר לְתוֹדָה, מִפְּנֵי שֶׁקָּרְבַּן תּוֹדָה בָּא בִּנְדָבָה, וְאֵין מְבִיאִים נְדָרִים וּנְדָבוֹת בַּשַׁבָּת וּבְיוֹם טוֹב. גַּם אֵין אוֹמְרִים אוֹתוֹ בְּחֹל הַמּוֹעֵד פֶּסַח, מִפְּנֵי שֶׁאֵין קָרְבַּן תּוֹדָה בָּא אָז, לְפִי שֶׁעִם הַתּוֹדָה צְרִיכִין לְהָבִיא עֲשָׂרָה לַחְמֵי חָמֵץ. וְלֹא בְּעֶרֶב פֶּסַח כִּי שֶׁמָּא לֹא יוּכְלוּ לְאָכְלָם עַד זְמַן אִסּוּר חָמֵץ וְיִצְטָרְכוּ לְשָׂרְפָן. וְלֹא בְּעֶרֶב יוֹם הַכִּפּוּרִים, מִפְּנֵי שֶׁמְּמַעֵט זְמַן אֲכִילָתָם וּמֵבִיא קָדָשִׁים לִידֵי פְסוּל (נ"א).
At the time of the Beis HaMikdosh a Thanksgiving sacrifice, Korbon Todah, was brought by:
1) A person released from prison, 2) A seriously ill person who recuperated, 3) A person returning from a sea voyage, 4) A person travelling through the wilderness and arriving at his destination. As with other sacrifices, after the destruction of the Temple, we now substitute prayer and discussion of the korbonos. It is for this reason that in our prayers we mirror some aspects of the actual korbonos. Thus, on a day that a particular korbon is not brought, we do not say the prayer that represents that korbon.
Only communal sacrifices which have a set period within which they must be brought are permitted on Shabbos and Yom Tov. Individual korbonos, such as the Todah, or communal sacrifices that have no allotted time may not be brought on Shabbos and Yom Tov. A Todah (or any other korbon, for that matter) is not brought when the full time allotted for the eating of the korbon is not available (in this case—one day and the following night).
On Shabbos and Yom Tov Mizmor Lesodah is omitted because the Todah sacrifice is voluntary, and voluntary sacrifices may not be brought on Shabbos and Yom Tov. It is also omitted in the intermediary days of Pesach because a Todah sacrifice is not brought then, since, along with the Todah, ten leavened breads are also required. Pesach eve, too, [the Todah is not brought] since, [the breads) may possibly not be eaten by the time the chametz prohibition begins and they will have to be burnt. Yom Kippur eve, [too, the Todah is not brought] because the time for eating is diminished, causing sacrifices to become invalid.7For fear that not given enough time to be eaten they become נוֹתַר—leftovers which are pasul (invalid) and require burning.
תנא דבי אליהו כל השונה הלכות בכל יום מובטח לו שהוא בן העולם הבא שנאמר הליכות עולם לו אל תקרי הליכות אלא הלכות (נדה ע"ג.)