Gittin 55B

ומה טעם אמרו נודעה אינה מכפרת? שלא יאמרו מזבח אוכל גזילות.

And what is the reason that the rabbis said that if it is known that the sin-offering was obtained through robbery, it does not effect atonement? It is so that people not say that the altar consumes stolen property.

בשלמא לעולא ⁠– היינו דקתני חטאת. אלא לרב יהודה ⁠– מאי איריא חטאת, אפילו עולה נמי!

The Talmud attempts to clarify the two explanations. Granted, according to the opinion of Ulla, that the concern stems from the fact that the priests will be distraught, this is the reason that the tanna teaches the halakha with regard to a sin-offering: The priests partake of the meat of a sin-offering. If they find out that they ate an animal that was forbidden to them, i.e., an offering slaughtered counter to halakha, they are likely to become distraught. But according to the opinion of Rav Yehuda, that the concern is about the honor of the altar, why does the Mishnah mention specifically the case of a sin-offering; shouldn’t the same concern apply to a burnt-offering, as well, as it too is burned on the altar?

לא מיבעיא קאמר ⁠– לא מיבעיא עולה, דכליל היא; אלא אפילו חטאת נמי, דחלב ודם הוא דסליק לגבי מזבח, ואידך כהנים אכלי ליה; אפילו הכי גזור, שלא יאמרו מזבח אוכל גזילות.

The Talmud answers: The Mishnah is speaking utilizing the style of: It is not necessary, and the Mishnah should be understood as follows: It is not necessary to teach the halakha in the case of a burnt-offering, which is entirely consumed on the altar. In that case, people will certainly say that the altar consumes stolen property. But even in the case of a sin-offering, where only the fat and the blood go up to be consumed on the altar and the rest is consumed by the priests, even so they issued a decree and said that the stolen sin-offering does not effect atonement, so that people should not say that the altar consumes stolen property.