THE TWO LOAVES OF THE TODA OFFERING (Yerushalmi Halachah 5 Daf 5a)
משנה ועוד א''ר יהודה שתי חלות של תודה פסולות ומונחות על גג האצטבע כל זמן שהן מונחות כל העם אוכלין ניטלה אחת מהן תולין לא אוכלין ולא שורפין ניטלו שתיהן התחילו כל העם שורפין
(Mishnah): Rebbi Yehudah said further that there were two pasul [Chametz] loaves of the korban toda that would rest on the top of the bench. As long as they were resting there, the people continued to eat. When one was removed, they were Toleh (suspended)- they would not eat but they would also not burn [the Chametz]. When both were removed, the people began to burn [the Chametz].
רבן גמליאל אומר חולין נאכלין כל ארבע ותרומה כל חמש ושורפין בתחילת שש
(Raban Gamliel): Chulin (non-sacred Chametz) may be eaten for the entire 4th hour, (Chametz of) Terumah may be eaten for the entire 5th hour and they burn at the beginning of the 6th.
גמרא ר' שמעון בן לקיש אמר בשם רבי ינאי כשירות היו
(Gemara - Rebbi Shimon ben Lakish): [The Toda loaves were not totally invalid, rather] they were kasher (valid).
משם מאי הוא פוסלן
Question: So in what way were they pasul?
שלא לשהות עליהן את הזבח
Answer: The sacrifice (which they were supposed to accompany) was not slaughtered. (Note: This answer follows the alternative text which the Korban ha'Edah explains.)
[דף ה עמוד ב] ולא בשחיטה הן קדושות ויפדה ויאכל
Question: Since the toda had not been slaughtered and therefore they did not have kedushas haguf (they were not consecrated until the time of slaughtering), one should be able to redeem them and eat them?!
אמר רבי חנניה חולייא קומי לא אוכל ואת אמרת יפדה ויאכל
Answer (Rebbi Chananyah): There is [already a large amount of] Chulin before him which he will not be able to eat (before the time of biur), so would he redeem [even more Chametz] to eat?!
רבי אמר פסולות היו מפני שהן ממהרין להביא תודותיהן מפני חמץ שבתודה ואי איפשר שלא ישפך דמה של אחד מהן והיא נפסלת
Answer #2 (instead of 1c) (Rebbi): They were actually pasul (invalid) as many would rush to bring their todas (on Erev Pesach - as on Pesach they could not be brought because they were Chametz), and it was impossible to avoid some of their blood being spilled, thereby invalidating the korban.
FURTHER EXAMPLES OF SIGNS (Yerushalmi Halachah 5 Daf 5b)
תני שתי פרות חורשות בירושלם
(Beraisa): Two cows would be ploughing in Yerushalayim (to be used as a sign as to when Chametz would be prohibited, in the same way that the two loaves were used).
וירושלם לא במקום שנהגו שלא לעשות מלאכה בארבעה עשר הוא
Question: Surely the custom in Yerushalayim was to refrain from melacha (creative labor) in the morning of the 14th?
נראות כחורשות
Answer: They appeared as if they were ploughing.
אית תנויי תני שתי נרות דולקין
(Beraisa version #1): Two candles were burning (and they would be an indication, in the same way as the loaves).
אית תנויי תני שני סדינין
(Beraisa version #2): Two sheets were suspended.
[דף ז עמוד א (עוז והדר)] אמר רבי פינחס ולא פליגון מאן דאמר שתי פרות שתי נרות בחול. מאן דמר שני סדינין בשבת
Resolution (Rebbi Pinchas): They do not disagree - The cows and candles were used [when the 14th occurred] on a weekday. The sheets were used [when the 14th occurred] on Shabbos.
רבי חנניה בעא קומי רבי מנא ויקבעו לה תקיעה
Question (Rebbi Chananyah to Rebbi Mana): Why did they not blow a shofar as a sign?
א''ל אם אומר את כן נמצאתה אומר שמא לתמיד הן תוקעין והן מתקלקלין
Answer: People might mistakenly think that it was for the (morning) Tamid offering (and this would result in people eating Chametz after the permitted time).
א''ל והא תנינן שלש להבטיל את העם מן המלאכה. ושלש להבדיל בין קודש לחול
Objection (Rebbi Chananyah - Mishnah): They would sound three blasts to stop the people from working and three blasts to signify the beginning of Shabbos. (Why is there no concern that people might mistakenly think that they were for the (afternoon) Tamid offering?)
א''ל תמן כל ערב שבת ושבת הן תוקעין ואינן טועין. ברם הכא אחת לקיצין הן אם אומר את כן אף הן סבירין שמא לתמיד הן תוקעין והן מתקלקלין
Answer: Since they would blow every Friday, people would not err; but here (erev Pesach) only occurred once a year, so people might confuse it with the Tamid offering.
THE OPINION OF RABBAN GAMLIEL IN THE MISHNAH (Yerushalmi Halachah 5 Daf 5b)
למה מפני קדושתה או משום שאין אוכליה מצויין
Query: Why did Raban Gamliel say that Terumah may be eaten for the entire 5th hour - did Chazal add an hour because of its sanctity or because there are not many people who can eat it (since it is prohibited to non-Kohanim)?
מה נפיק מביניהון
Question: Where is there a practical difference?
חלות תודה. אין תימר שאין אוכליה מצויין. אלו אוכלין מצויין. אין תימר מפני קדושתה אלו יש להן קדושה
Answer: Todah loaves (that are sanctified but are permitted to non-Kohanim). If the reason is because there are not many people who can eat Terumah, all can eat the loaves. If the reason is because of the sanctity of Terumah, these are also sanctified.
[דף ו עמוד א] ר' נתן אומר כשירות ניטלו שוהין להן שעה אחת לאכילתן ותולין אבל לא שורפין
Answer (Beraisa - Rebbi Nosson): When they took the [two] kasher loaves (that were placed on top of the bench - see Mishnah in 1a) they continued to eat them for an hour. The Chulin was suspended but not burned.
אית לך מימר משום שאין אוכליה מצויין לא מפני קדושתה. אוף הכא מפני קדושתה
Proof: The reason for here is not because there are only few people who can eat it (since this does not apply to the toda loaves as non-Kohanim could eat them), rather it is because of their sanctity. Here also, the reason for Terumah is because of its sanctity.
א''ר יודה בן פזי נראין דברים שתהא הלכה כרבן גמליאל שהוא אומר מעין שניהן
(Rebbi Yuda ben Pazi): It appears that the halacha should follow Raban Gamliel as he (partially) follows both of them (Rebbi Meir in Terumah and Rebbi Yehudah in Chulin (Pnei Moshe)).
אתא ר' אבון ר' יוחנן בשם רבי שמעון בן יוצדק הלכה כרבן גמליאל שהוא אומר מעין שניהן
Rebbi Avun reiterates this in the name of Rebbi Shimon ben Yutzedek.