THE OPINION OF R. YEHOSHUA (Yerushalmi Terumos Perek 8 Halachah 1 Daf 39b)
ø' çâé ùàì ìçáøééà îðééï ìàåëì áøùåú ùäåà ôèåø îä áéï ñáø ùäåà çåìéï [ãó î òîåã à] åðîöà úøåîä ùäåà çééá îä áéï ñáø ùäåà (éùøàì)[ëäï] åðîöà (ëäï)[éùøàì] ùäåà ôèåø
Question (R. Chaggai to Chevraya): Why did R. Yehoshua exempt all of those who ate Terumah and later found out that they weren't permitted? How is it different to when a person thought that he was a Kohen and he was found to be a Yisrael, that according to R. Yehoshua, he is exempt?
àîøéï ìéä îäåøééú á''ã
In the case of the Kohen, he only becomes disqualified if witnesses came to Beis Din, and until the ruling is made, he is permitted to eat Terumah.
àîø ìåï òåã öøéëä ìé îä áéï ñáø ùäåà çåì åðîöà ùáú ùäåà çééá îä áéï ñáø ùäåà ôñç åðîöà ùìîéí ùäåà ôèåø
Another question (R. Chaggai to Chevraya): Why when a person did a Melacha on Shabbos, thinking that it was a weekday, is he liable to bring a Chatas offering; but when a person slaughtered on Erev Pesach that occurred on Shabbos, thinking that it was a Pesach offering when it was in fact a Shelamim offering, does R. Yehoshua says that he is exempt from a Chatas?
[ãó î òîåã á] àîøéï ìéä îùåçè áøùåú
Answer (Chevraya): Since he thought he was slaughtering a Pesach offering, it was a case of making a mistake in trying to fulfil a Mitzvah and R. Yehoshua exempts.
[ãó òà òîåã á (òåæ åäãø)] àîø ìåï òåã öøéëä ìé îä áéï ñáåø ùäåà ùåîï åðîöà çìá ùäåà çééá îä áéï ñáåø ùäåà àñåø åðîöà îåúø ùäåà ôèåø
Another question (R. Chaggai to Chevraya): Why when a person ate permitted fats and then discovered that it they were prohibited fats, is it considered inadvertent and he is liable to bring a Chatas; but when he tried to eat prohibited fats and permitted fats came to his hand, he is exempt from a Chatas?
ìà (àâéáå)[àâéáåðéä] îä àîø ìåï ðîìëéï îéðï
They did not answer that question. R. Chaggai said to them, "Let's investigate the reason''...
àå äåãò àìéå çèàúå åäáéà äùá îéãéòúå çééá òì ùââúå éöà æä ùàôéìå éåãò àéðå ôåøù
(R. Chaggai): The pasuk states (Vayikra 4:28), "...if his sin that he committed is made known to him, he shall bring (his sacrifice)...'' - this implies that had he known at the time that it was prohibited, he would not have done the sin. This excludes our case where he would not have refrained, since the act was permitted.
òàì øáé éåñé ìâáåï
R. Yosi then came into the Beis Midrash (and they asked him the question)...
àîø ìåï ìîä ìà àîøéúå ìéä àå äåãò àìéå çèàúå åäáéà
(R. Yosi): Why didn't you tell R. Chaggai that the pasuk states "...if his sin that he committed is made known to him, he shall bring (his sacrifice)...'' etc.?
àîøéï ìéä äåà ÷ùéúä åäåà ÷ééîä.
(Chevraya to R. Yosi): He asked the question and he answered it himself from that pasuk.