Mizmor LeTodah
Overview
There are different opinions of when to say Mizmor LeTodah: Some said it always, some said it only on Shabbat and others only on Chol. The Avudraham said Mizmor LeTodah always, both on Shabbat and Chol and that seems to be the custom in early Spain. The minhag to say Mizmor LeTodah only on Shabbat is an Italian minhag which is found in Shibolei HaLeket and Italian siddurim nowadays. In Germany, France and late Spain they said Mizmor LeTodah only on Chol.
The early Minhag seems to have been to say Mizmor LeTodah only on Shabbat since there wasn't enough time on Chol. Later on it was added also to Chol. Although, then some people had a problem with saying Mizmor LeTodah on Shabbat since the korban todah wasn't brought then. In France and Germany they stopped saying Mizmor LeTodah on Shabbat and only later did that minhag get adopted in Spain. R. Eliyahu (brought in the Rokeach) and the Maharil tried to solve the problem of korban todah and did a פשרה, they said Mizmor LeTodah but without the first two words.
Geonim Mizmor LeTodah is not mentioned in any Tannaim or Amoraim literature. It is first found in Siddur R. Amram Gaon as being said on Shabbat. It is not found in Siddur Rasag or any other Geonic source. Most probably it was said just on Shabbat because there wasn't enough time on Chol.
Rishonim
During the Rishonim time there were different opinions of when to say Mizmor LeTodah:
- Italy – In Italy they said Mizmor LeTodah only on Shabbat like the early minhag. שבולי הלקט says that the reason for that is because קרבן תודה is not going to be מתבטל לעתיד לבוא and Shabbat is like לעתיד לבוא.
- Spain – In Spain Mizmor LeTodah was said both on Shabbat and on chol.
- Ashkenaz and France – In Ashkenaz and France they said Mizmor LeTodah only on chol since on Shabbat one is not מקריב a קרבן תודה. R. Eliyahu (mentioned in the רוקח) and the מהרי"ל say that one should say it also on Shabbat just skip the first two words of "מזמור לתודה".