Reference for Pesachim 1:5
וְעוֹד אָמַר רַבִּי יְהוּדָה, שְׁתֵּי חַלּוֹת שֶׁל תּוֹדָה פְסוּלוֹת מֻנָּחוֹת עַל גַּג הָאִצְטַבָּא. כָּל זְמַן שֶׁמֻּנָּחוֹת, כָּל הָעָם אוֹכְלִים. נִטְּלָה אַחַת, תּוֹלִין, לֹא אוֹכְלִין וְלֹא שׂוֹרְפִין. נִטְּלוּ שְׁתֵּיהֶן, הִתְחִילוּ כָל הָעָם שׂוֹרְפִין. רַבָּן גַּמְלִיאֵל אוֹמֵר, חֻלִּין נֶאֱכָלִין כָּל אַרְבַּע, וּתְרוּמָה כָּל חָמֵשׁ, וְשׂוֹרְפִין בִּתְחִלַּת שֵׁשׁ:
R. Yehudah said further: Two chaloth [of chametz] of the todah (the thanksgiving offering) were pasul (unfit for eating) [having been rendered pasul by linah (passing the night without having been eaten)], and they were placed on the roof of the itzteva (the Temple portico). [For since there were many thanksgiving breads on the thirteenth of Nissan — for whoever had a todah to bring had to do so on the thirteenth — they (those which had not been eaten) became pasul by linah on the morning of the fourteenth. The thanksgiving breads consisted of forty chaloth, ten of them, chametz, and the todah could be eaten (only) on the (same) day and night. But if they were brought on the fourteenth, those of chametz could be eaten only until the sixth hour; and it is forbidden to bring an offering on a day when the time for eating it would be curtailed, for "Consecrated offerings are not brought to the house of psul." Therefore, whoever was obliged to bring a todah would do so on the thirteenth, not being able to bring it on the fourteenth (all the more so, on Pesach), so that they (i.e., some of them) became pasul by linah on the morning of the fourteenth, there not having been enough eaters. Therefore, because they were pasul, they were placed there (for if they were kasher, they would not place them there and render them pasul deliberately.) They were placed there until the time of removal and they were burned, and they were placed on the roof of the itzteva to be visible as a sign.] So long as they were lying there, all the people ate (chametz). When one of them was removed [At the beginning of the fifth hour, the messenger of beth-din came and removed one, whereby all the people understood that the fifth hour had arrived and] they "suspended" (activity) — they neither ate nor burned (chametz). When both had been removed, all the people began to burn (their chametz). R. Gamliel says: Chullin (mundane food) is eaten all four (hours); terumah, all five, [it being forbidden to deliberately waste consecrated food so long as one is permitted to eat it], and it is burned at the beginning of the sixth, [for most people can confuse the seventh with the sixth. The halachah is not in accordance with R. Gamliel.]