LEAVEN / UNLEAVENED BREAD
When God delivered the Israelites under the leadership of Moses, God asked them to celebrate the Passover. Since they had to leave Egypt immediately after in a hurry, they could not wait to leaven the bread. So, God asked the Israelites to celebrate annually the feast of the Unleavened Bread for one week to remember gratefully that historical event. “The fifteenth day of this month is the LORD’s feast of Unleavened Bread. For seven days you shall eat unleavened bread” (Lev 23:6).
Israel had to give up all their sinful ways in Egypt and follow the Lord to the Promised Land. Since leaven was a symbol of sin, part of Passover preparation was the scrupulous removal of all leaven from the house before the celebration.