Jewish people around the world are preparing to observe the important Jewish holiday of Passover ~ Pesach ~ פסח. (In 2017, Pesach will begin in the evening of 10 April and end in the evening of 18 April). Passover is celebrated as a commemoration of their liberation from slavery in Egypt and their freedom as a nation under the leadership of Moses. It commemorates the story of the Exodus as described in the Hebrew Bible especially in the Book of Exodus , in which the Israelites were freed from slavery in Egypt. According to standard biblical chronology, this event would have taken place at about 1300 BCE (AM 2450). Passover is a spring festival which during the existence of the Jerusalem Temple was connected to the offering of the "first-fruits of the barley", barley being the first grain to ripen and to be harvested in the Land of Israel. Passover commences on the 15th of the Hebrew month of Nisan and lasts for either seven days (in Israel and for Reform Jews and other progressive Jews around the world who adhere to the Biblical commandment) or eight days for Orthodox, Hasidic and most Conservative Jews (in the diaspora). In Judaism, a day commences at dusk and lasts until the following dusk, thus the first day of Passover only begins after dusk of the 14th of Nisan and ends at dusk of the 15th day of the month of Nisan. It is one of the most widely observed Jewish holidays.