reports that Levites of the sons of Kehath and of the sons of Korah extolled God in song. Eleven psalms identify themselves as of the Korahites. Numbers chapter 9 Passover refers to the Festival of Passover. In the Hebrew Bible, Passover is called: "Passover" (, Pesach); "The Feast of Unleavened Bread" (, Chag haMatzot); and "A holy convocation" or "a solemn assembly" (, mikrah kodesh). Some explain the double nomenclature of "Passover" and "Feast of Unleavened Bread" as referring to two separate feasts that the Israelites combined sometime between the Exodus and when the Biblical text became settled. and indicate that the dedication of the firstborn also became associated with the festival. Some believe that the "Feast of Unleavened Bread" was an agricultural festival at which the Israelites celebrated the beginning of the grain harvest. Moses may have had this festival in mind when in and he petitioned Pharaoh to let the Israelites go to celebrate a feast in the wilderness. "Passover," on the other hand, was associated with a thanksgiving sacrifice of a lamb, also called "the Passover," "the Passover lamb," or "the Passover offering." , , and and 5, and direct "Passover" to take place on the evening of the fourteenth of , Aviv (, Nisan in the Hebrew calendar after the Babylonian captivity). , , , and confirm that practice. , , and , , and direct the "Feast of Unleavened Bread" to take place over seven days and and direct that it begin on the fifteenth of the month. Some believe that the propinquity of the dates of the two Festivals led to their confusion and merger. and 27 link the word "Passover" (, Pesach) to God's act to "pass over" (, pasach) the Israelites' houses in the plague of the firstborn. In the Torah, the consolidated Passover and Feast of Unleavened Bread thus commemorate the Israelites' liberation from Egypt. The Hebrew Bible frequently notes the Israelites' observance of Passover at turning points in their history. reports God's direction to the Israelites to observe Passover in the wilderness of Sinai on the anniversary of their liberation from Egypt. reports that upon entering the Promised Land, the Israelites kept the Passover on the plains of Jericho and ate unleavened cakes and parched corn, produce of the land, the next day. reports that King Josiah commanded the Israelites to keep the Passover in Jerusalem as part of Josiah's