“Your lamb shall be an unblemished male a year old...And you shall keep it until the fourteenth day of the same month, then the whole assembly of the congregation of Israel is to kill it at twilight. Moreover, they shall take some of the blood and put it on the two doorposts and on the lintel of the houses in which they eat it. And they shall eat the flesh that same night, roasted with fire, and they shall eat it with unleavened bread and bitter herbs...and you shall eat it in haste–it is the Lord’s Passover. For I will go through the land of Egypt on that night, and will strike down all the first-born in the land of Egypt, both man and beast; and against all the gods of Egypt I will execute judgments–I am the Lord. And the blood shall be a sign for you on the houses where you live; and when I see the blood I will pass over you, and no plague will befall you to destroy you when I strike the land of Egypt...
“Now it came about at midnight that the Lord struck all the first-born in the land of Egypt, from the first-born of Pharaoh who sat on his throne to the first-born of the captive who was in the dungeon, and all the first-born of cattle. And Pharaoh arose in the night...Then he called for Moses and Aaron at night and said, ‘Rise up, get out from among my people, both you and the sons of Israel; and go, worship the Lord, as you have said.’” (Exodus 12:5-8, 11-13, 29-31)
“In the first month, on the fourteenth day of the month at twilight is the Lord’s Passover. Then on the fifteenth day of the same month there is the Feast of Unleavened Bread to the Lord; for seven days you shall eat unleavened bread.” (Leviticus 23:5-6)
The Diaspora or Jews living outside of Israel celebrate an eight day Passover (Nisan15-22) while Jews living in Israel hold a seven day Passover celebration (Nisan 15-21). The Jewish month of Nisan roughly coincides with our contemporary month of April. After reading the scriptural passages above, one might ask, “What happened to Nisan 14? Surely it should be included in the Passover celebration held by the Jews.”