Matzo is the unleavened bread baked in great haste by the children of Israel on the eve of their flight from Egypt (Exodus 12:8). Every year at Passover, or the Feast of Unleavened Bread, the eating of matzo and the purging of all leavened products from the home commemorate this flight (Exodus 12:15–39, 13:6–7, and 23:15). Unleavened bread is the only food the children of Israel are actually commanded to eat in the Hebrew Bible. In this sense, matzo is the most Jewish food there is. The foods that are called Jewish foods are almost always the regional foods from areas where Jews have settled in large numbers. These Jewish foods may be different from the local non-Jewish food, but they bear more resemblance to non-Jewish food of their own region than to Jewish food from far away. The exception is matzo. Every Jewish community has some variation of matzo. The variations in shape and thickness, however, are minor, since the laws of matzo manufacture are so very specific. All matzo must be prepared in less than eighteen minutes from the moment water comes into contact with flour to the moment the fully baked matzo emerges from the oven.