'Unleavened' in the Bible

'Thou dost not eat with it any fermented thing, seven days thou dost eat with it unleavened things, bread of affliction; for in haste thou hast come out of the land of Egypt; so that thou dost remember the day of thy coming out of the land of Egypt all days of thy life;

six days thou dost eat unleavened things, and on the seventh day is a restraint to Jehovah thy God; thou dost do no work.

Three times in a year doth every one of thy males appear before Jehovah thy God in the place which He doth choose -- in the feast of unleavened things, and in the feast of weeks, and in the feast of booths; and they do not appear before Jehovah empty;