Pesachim 13 - Chametz sign for the people
Ideally, one should consume the chametz and not destroy it, especially if this bread belongs not to himself but to someone else. For example, if Passover falls out on Sunday, so that one won’t be able to burn it on a day before, which is Shabbat - what is one to do with the Kohen’s portion of the bread in his possession? In this case the Rabbi Yehoshua allows him to burn it on Friday, but the Sages still require him to wait - perhaps a Kohen will chance to his house on Saturday.
Rabbi Yehoshua counters that if no Kohen was in town in Friday then he won’t come on Saturday - because one cannot travel on Shabbat, but the Sages say that a Kohen might be on the road close by. "If you are so careful," - said Rabbi Yehoshua - "then why did you allow burning Kohen’s portion which may have become impure? Perhaps Elijah the Prophet will come and reveal that this bread is pure?" To which the Sages replied that it is well know that Elijah will not come on Friday when the Jews are busy preparing for Shabbat.
In the Temple there was a sign for the people: two unused breads were lying on the roof while chametz could be eaten; one was hidden when they had to refrain from eating, and the last was taken away when the time to burn chametz arrived.
Art: A panoramic landscape with travellers on a road, a town beyond by (after) Jan, The Younger Brueghel