Know ye not that a little leaven leaveneth the whole lump? Purge out therefore the old leaven, that ye may be a new lump, as ye are unleavened. For even Christ our passover is sacrificed for us: Therefore let us keep the feast, not with old leaven, neither with the leaven of malice and wickedness; but with the unleavened bread of sincerity and truth. (1 Cor 5:6-8)
Some commentators believe that Paul wrote the letter of 1 Corinthians during the late winter or early spring because of his reference here to Christ as our Passover lamb. (Passover/Pesach starts March 28 this year.) Whether it was written around Pesach or not, it wouldn't hurt at this time to look at that to which Paul made reference.
The rules regarding the Passover lamb were very specific. Only certain lambs could qualify. Even once it was chosen the killing and eating of the lamb fell under clear limitations.
In the tenth day of this month they shall take to them every man a lamb, according to the house of their fathers, a lamb for an house: And if the household be too little for the lamb, let him and his neighbour next unto his house take it according to the number of the souls; every man according to his eating shall make your count for the lamb. Your lamb shall be without blemish, a male of the first year: ye shall take it out from the sheep, or from the goats: And ye shall keep it up until the fourteenth day of the same month: and the whole assembly of the congregation of Israel shall kill it in the evening. And they shall eat the flesh in that night, roast with fire, and unleavened bread; and with bitter herbs they shall eat it. And ye shall let nothing of it remain until the morning; and that which remaineth of it until the morning ye shall burn with fire. (Ex 12:3-6,8,10)
Thou shalt not offer the blood of my sacrifice with leaven; neither shall the sacrifice of the feast of the passover be left unto the morning. (Ex 34:25)
They shall leave none of it unto the morning, nor break any bone of it: according to all the ordinances of the passover they shall keep it. (Ex 9:12)
As with any meat, the blood of the Passover lamb was to be fully drained from the body. The blood was to be sprinkled on the doorposts and lintels. Anyone who refused to participate in the Passover was to be "cut off" from the people.
By saying that Christ is our Passover lamb, Paul is saying that he met the requirements to be offered for the salvation of the people. In what ways did Jesus meet these qualifications?
Exodus 12 specified that the lambs were to be selected on the tenth day of the month, four days before they were offered. Once the Temple was built and Jerusalem was selected as the place where the people were to eat the Passover the lambs were brought into the city on that date. If one follows the timeline set forth by Matthew and Mark in their gospels, Jesus made his triumphal entry at the same time that the shepherds were bringing the lambs into the city. That was one reason the moneychangers were in the Temple at the time he drove them out. So Jesus meets the requirement that the lamb be brought in on the tenth of the month.
Why did Jesus say, as recorded in John 7:6 that his time was not yet come? He knew, according to verse 19 that there were those seeking his life. But the feast to which he was going at that time was the Feast of Tabernacles. He knew he could not die during that feast, but must die during the Passover? Why? Because the lamb had to be offered without leaven. For Jesus to be our Passover he had to die during the one week of the year when no leaven was to be found in Jerusalem. In John 7 he says, "My time is not yet come." In contrast, in Matt 26:18 he says, "Go into the city to such a man, and say unto him, The Master saith, My time is at hand; I will keep the passover at thy house with my disciples." He knew he was to be sacrificed at the Passover. He knew the time had come.
The lamb was to be "without blemish." The writer of Hebrews twice points out that Jesus was "without sin"-Heb 4:15 and Heb 9:28. In the context of this latter passage the writer even calls Jesus a "better sacrifice." Peter also equates Jesus to the Passover lamb. "Forasmuch as ye know that ye were not redeemed with corruptible things, as silver and gold, from your vain conversation received by tradition from your fathers; But with the precious blood of Christ, as of a lamb without blemish and without spot." (1 Pet 1:18-19)
No bones of the paschal lamb were to be broken, and yet blood was shed. Again, Jesus uniquely meets these requirements. Roman crucifixions were often bloodless affairs. More often than not the victim was tied to the cross. On most occasions they were left on the cross for days until they died a slow, hungry, painful death. Their death was not facilitated by any weapons. But look at Jesus' case. He was nailed to the cross. In John 20, Thomas points out that his hands and feet should have nail prints. Mere nails, though, would not draw enough blood. So, contrary to custom, it happened that "one of the soldiers with a spear pierced his side, and forthwith came there out blood and water." (Jn 19:34) The normally bloodless execution was inexplicably accompanied by a piercing with a spear. Normally no bones would be broken anyway. On this occasion, because of the Sabbath, it was planned that the legs of the victims would be broken. Yet when they came to Jesus and found him dead they did not break his legs. This was planned by God, "For these things were done, that the scripture should be fulfilled, A bone of him shall not be broken." (Jn 19:36)
Another requirement was that the lamb was not to be left until the morning. That Jesus did not hang on the cross for several days was no coincidence. Had he done so he could not be our Passover. He was sacrificed on the day before a Sabbath for a reason. His executioners, either Jewish or Roman, did not suspect that they were doing God's will by executing him that day.
Perhaps we can now see what Paul saw. Jesus the Christ is our Passover lamb because he meets the requirements set forth for that lamb.
Does it make a difference to us that Jesus is our Passover? Particularly since many of the Corinthians were Gentiles, and since most Christians today are Gentiles, what does it matter that Jesus met the requirements of a Jewish sacrifice?
The simple answer would be that Paul was a Jew and therefore kept the Passover. There were probably some Jewish Christians at Corinth who would understand his point, and they could explain it to their Gentile brothers. That would be the simple answer, but I think there is more to it than that.
Paul did not say Christ was "the Jew's Passover." He said "our Passover is sacrificed for us." In Jesus the Passover extends even to the Gentiles. According to the Law of Moses nobody outside the fellowship of Judaism could partake of the Passover. But Paul is now saying that the Passover was for everyone. Not that everyone needs to fulfill all the specifics of the Passover observance, but the reason for the observance now applies to all.
The Passover lamb was sacrificed to save Israel from the plague of the death of the firstborn in Egypt. Another requirement of the lamb was that it be a firstborn, thus replacing the firstborn of the Israelites in the plague. We are all under sentence of death, be we firstborn or not. Jesus shed his blood to save us from the sentence of death, just as the firstborn of Israel were saved. Paul tells the Colossians that Jesus met this last requirement of the lamb.
Who is the image of the invisible God, the firstborn of every creature: For by him were all things created, that are in heaven, and that are in earth, visible and invisible, whether they be thrones, or dominions, or principalities, or powers: all things were created by him, and for him: And he is before all things, and by him all things consist. And he is the head of the body, the church: who is the beginning, the firstborn from the dead; that in all things he might have the preeminence. (Col 1:15-18)
Did we need a Passover sacrifice? Without one we were doomed to spiritual death. What did God do about it? He provided a firstborn without blemish as our Passover lamb. Because of him we need not suffer the fate of Egypt. Because of him we have life.