Made without yeast, and ordered for cereal offerings in the Temple (Lev. 2: 4, 11). The theory was that the process of fermentation was a kind of corruption from a previously pure condition (1 Cor. 5: 8).
During the festival of Unleavened Bread at the beginning of harvest only unleavened bread was eaten. This custom was grafted on to Israelite history by being associated with the Exodus when, according to the tradition, the people left Egypt in such haste that the women did not even have time to let the dough rise (Exod. 12: 14–20). Thus Unleavened Bread and Passover came to be regarded as one festival.