'Unleavened' in the Bible

You shall not eat leavened bread with it; instead, for seven days you shall eat the Passover with unleavened bread, the bread of affliction (for you left the land of Egypt in haste); [do this] so that all the days of your life you may remember [thoughtfully] the day when you came out of the land of Egypt.

For six days you shall eat unleavened bread, and on the seventh day there shall be a celebration to the Lord your God; so you shall do no work [on that day].

“Three times a year all your males shall appear before the Lord your God in the place which He chooses, at the Feast of Unleavened Bread (Passover) and at the Feast of Weeks (Pentecost) and at the Feast of Booths (Tabernacles), and they shall not appear before the Lord empty-handed.