Pesachim 53B

קרוב להאכיל את ישראל קדשים בחוץ. מקולס ⁠— אין, שאין מקולס ⁠— לא! אמרי, מקולס: לא שנא אמר, לא שנא לא אמר. שאינו מקולס: פירש ⁠— אין, לא פירש ⁠— לא.

Doing so is akin to feeding Jews consecrated meat outside the permitted area, as due to its resemblance to the Paschal lamb it could be misleading. The Talmud analyzes this statement: A goat roasted whole, yes, it is prohibited; a goat not roasted whole, no, it is not prohibited. This contradicts Rav, who prohibited roasting even ordinary meat. The rabbis say that this is the distinction: With regard to a goat roasted whole, there is no difference if one said it is for Passover, and there is no difference if one did not say it is for Passover. In either case, it looks like a sacrifice and it is prohibited. With regard to a goat not roasted whole, if one specified that it is for Passover, yes, it is prohibited because it appears that he is consecrating it as a sacrifice. However, if one did not specify that it is for Passover, no, it is not prohibited, as there is no need for concern.

רב אחא מתני לה להא מתניתין כרבי שמעון. מתקיף לה רב ששת: בשלמא למאן דתני לה כרבי יוסי ⁠— ניחא, אלא למאן דמתני כרבי שמעון ⁠— מי ניחא?

Rav Aḥa teaches this baraita about Theodosius in accordance with the opinion of R' Shimon. Rav Sheshet strongly objected to this: Granted, according to the one who learns it in accordance with the opinion of R' Yosei, it works out well. However, according to the one who teaches it in accordance with the opinion of R' Shimon, does it work out well? Didn’t we learn in a Mishnah about a dispute with regard to one who consecrated an item for a purpose for which it was unsuited, e.g., a case where one sought to bring a meal-offering of barley, although meal-offerings may be brought only from wheat? In that case, the Rabbis say he is required to bring a meal-offering of wheat because in the first part of his statement he vowed to bring a meal-offering.