Neighbors in Jerusalem gathered and participating in burning the pile of leavened bread.
Passover is also called the feast of unleavened bread. First day of the Jewish Passover holiday celebrated with the public burning of heaps of leavened bread (Hametz). All leaven products are burned this day to make homes ready for the holiday. Once the eight-day celebration begins (It starts after the Sunset with appearance of the first stars in the sky), when observant Jews and followers of Jewish tradition will eat only unleavened foods (Matzah). When the Jews fled Egypt, they did not wait for the bread to rise. They needed to speed up the process; “Don’t even let any leavening touch the dough. Just bake it and go.”
As also in some other cultures Yeast (or leaven) represents sin, corruption and spoiling, burning unleavened bread is the part cleansing process.