Moses gathered the Israelite elders and conveyed to them G‑d’s instructions.

G‑d gave the Israelites their first mitzvah, that of determining the New Moon (Rosh Chodesh) each month and establishing a lunar calendar. Moses also instructs the Israelites to designate a lamb for the Paschal offering. The Israelites were to sacrifice this lamb and consume it, together with matzah and bitter herbs, on the eve of the fifteenth of Nissan. The blood of the lamb was to be smeared on the lintels and doorposts of the Israelite residences, and all inside those homes would be spared when G‑d descended to smite the Egyptian firstborn. Moses also instructed that for all future generations this day would signal the beginning of the seven-day holiday of Passover, during which no leaven may be eaten or possessed.