One may not purchase terumah with money of maaser sheni, because he lessens its consumption. But R' Shimon permits. Said to them R' Shimon: If He was lenient with respect to shelamim offerings which leads to [prohibitions of] pigul, nosar, or tamei, shall we not be lenient with respect to terumah? They said to him: If He was lenient with respect to shelamim offerings which are permitted to non-Kohanim, shall we be lenient with respect to terumah, which is forbidden to non-Kohanim?