Just as the first exodus was preceded by the institution of the Passover, the greater new exodus was preceded by the institution of the Lord’s Supper. Jesus instituted the Lord’s Supper on this night to signify that this new exodus was about to begin. This act indicated that the time of redemption had come.
As the book of Exodus begins, Israel has been in Egypt for more than four hundred years (cf. Ex. 12:40). They are now in bondage under an oppressive Pharaoh. The early chapters of Exodus describe the calling of Moses to be the one who will lead God’s people out of slavery in Egypt. He comes before Pharaoh demanding that Israel be allowed to go and worship the Lord, but Pharaoh refuses. God then sends a series of increasingly severe plagues on Egypt. Pharaoh’s stubbornness in the face of the first nine plagues results in God’s pronouncement of a final plague that will result in Israel’s redemption from slavery. God warns that He will go into the midst of Egypt and that every firstborn in the land will die. It is in the context of the warning of this final plague that we find God’s instructions regarding the Passover in Exodus 12.
God begins with a statement indicating that the Passover and Exodus will mark a new beginning for the nation of Israel. The month of Abib (late March and early April) is to be the first month of the year for God’s people. This emphasizes the fact that the exodus from Egypt is a key event, a turning point, in redemptive history. So central is the event that from this point forward, God is frequently described in reference to the exodus (e.g., Ex. 20:2; Lev. 11:45; Num. 15:41; Deut. 5:6; Josh. 24:17; Judg. 6:8; 1 Sam. 10:18; 2 Kings 17:36; Ps. 81:10; Jer. 11:4; Dan. 9:15; Hos. 11:1; Amos 2:10). He is identified as the One who redeemed His people from slavery.
In later years, the observation of the Passover would involve the priesthood (cf. Deut. 16:5–7), but on the night of the original Passover, the responsibility for this ceremony falls to the head of each household. The head of every household is commanded to take a male lamb that is one year old and without any blemishes. This substitutionary lamb must be a symbol of perfection. As such, it foreshadows the true Lamb of God, Jesus Christ, who was uniquely without blemish (cf. 1 Peter 1:19). At twilight, the lamb for each household is to be killed.
The Lord then reveals what the Israelites are to do with the slain lambs and why they are to do it. Each head of a household is to take the blood of the lamb and put it on the doorposts and lintel of his house. God explains that the blood will be a sign. When He sees the blood on the door, He will pass over that house, and the firstborn in it will be spared from the coming judgment that is to fall on Egypt. After the lambs are killed by the head of the household, they are to be roasted and eaten with the people dressed and prepared to leave on a moment’s notice. Since the Passover is a “sacrifice” (cf. Ex. 12:27; 34:25; Deut. 16:2), the eating of the lamb is a sacrificial meal like that associated with the peace offering described in Leviticus 3 and 7. In such meals, the body of the sacrificial victim is offered to believers to eat after the sacrifice is made (Lev. 7:15).