Chapter 1, Mishna 4
Rav Nachman said in the name of Rav, the law accords with Rabbi Yehuda over Rabbi Meir regarding the last hour to eat leaven on the eve of Passover. But does it? Related cases are brought on feeding chametz to one’s animal, removing consecrated leaven when the eve of Passover falls on Shabbos, and when we sell someone else’s leaven to a non-Jew. Also, using consecrated loaves and plowing cows to signal to the nation when the time of eating leaven has ended and an hour later, when the time of removing leaven from our possession has arrived.