Parashas Bo · Shemos 12:15 · TT note 1
Torah Temimah on Shemos 12:15, note 1 (on שִׁבְעַת יָמִים מַצּוֹת תֹּאכֵלוּ) points to Pesachim 38b.
Sefaria — Exodus 12:15
Sefaria — Torah Temimah on Exodus 12:15
Sefaria — Pesachim 38b
E-Daf — Pesachim 38b
English: One might think a person fulfills his obligation with challos of a todah or wafers of a nazir — Scripture says “seven days you shall eat matzos”: matzah that is eaten for seven days. This excludes that which is eaten only for a day and a night.
Exclusion: obligation-matzah must be of the seven-day kind, not sacrificial matzah limited to a day and night.
One does not fulfill the mitzvah of matzah with challos of todah or rekikei nazir, which are not eaten for the full seven days.