What is unleavened festival?

One of the three Jewish festivals. According to Baidu Encyclopedia, the Feast of Unleavened Bread commemorates that when the Israelites were in Egypt, the Lord God killed the eldest son of the Egyptians, crossed the houses of the Israelites (that is, crossed the houses with the blood of lambs on their doors) and saved the whole family of Israel. Unleavened Bread is also called Unleavened Bread and Passover. The second day of Passover, that is, the fifteenth day of Abib, is the time to harvest barley. From the first day of the festival to the 2nd1day of this month, people only eat unfermented food, but not fermented food. They also hold religious meetings and cannot work. They should pray for God's blessing to ensure a bumper harvest.