Shabbat 25B

ואין לה פדיון, ואסורה לזרים. הנך נפישן.

And, teruma does not have the possibility of pidyon: redemption, as, once it is sanctified, it may not be redeemed and rendered non-sacred. And it is prohibited to zarim: non-priests may not eat it. These stringencies do not apply to consecrated items. The Talmud answers: Nevertheless, those stringencies that apply to consecrated items are more numerous than those that apply to teruma. Therefore, it is appropriate to be more stringent with consecrated items and exclude impure teruma from the prohibition against deriving benefit when burning it.

ואיבעית אימא: קדש חמור שכן ענוש כרת. רב נחמן בר יצחק אמר, אמר קרא: ״תתן לו״. ״לו״⁠ — ולא לאורו. מכלל דבת אורו הוא.

And if you wish, say instead a different reason, without counting the number of stringencies: Consecrated items are more stringent because one who eats them while ritually impure is punishable by karet, while in the case of teruma the punishment is death at the hand of Heaven. In this regard, the Torah is more stringent vis-à-vis consecrated items than it is vis-à-vis teruma. Rav Naḥman bar Yitzḥak said that there is a different proof that one is permitted to benefit from teruma while it is burning. As the verse said: “The first fruits of your grain, of your wine, and of your oil, and the first of the fleece of your sheep should you give him” (Deuteronomy 18:4). The rabbis derived from this verse: Give the priest teruma that is ritually pure, that is fit for him to consume, and do not give the priest teruma that is suitable only for his fire, to be burned. By inference, ritually impure teruma is suitable for his fire, i.e., a priest may derive benefit from it.