I think this might help you to understand further?
The Fourth Cup by Scott Hahn(follow along with your Bible)
http://zuserver2.star.ucl.ac.uk/~vgg/rc/aplgtc/hahn/m4/4cp.html
Excerpt:
There's no mistaking the fact that St. John, the beloved disciple, understood our Lord's sacrifice as the culmination, the fulfillment of the Old Testament Passover. For instance, why is that Jesus happened to be wearing a seamless linen garment at the cross, when just coincidently that's what the priest was legislated to wear when he sacrificed the Passover? Here is the true priest, as well as the true victim. And when he was crucified, unlike the two thieves whose legs had to be broken to expedite death, his bones were not broken. Why? To fulfill the scripture where it says, “None of his bones shall be broken.” What's that talking about where it says, “None of his bones shall be broken”? One of the things is that if you took a lamb to sacrifice for the Passover and you discovered that it had a broken bone, you had to throw him out and get another one. The only fit sacrifice was a lamb without broken bones. John sees in this so much more than we can get into, but one thing in particular. Verse 28, “After this”_at the very end of his cruel sufferings_”Jesus, knowing that all was now finished said, in order to fulfill the scriptures, ‘I thirst.’” Now, he's been on the cross for hours. Is this the first moment of thirst. No, he'd been wracked with pain and dying of thirst for hours. But he says, in order to fulfill the scripture, “I thirst.” Why? To fulfill the scripture.
“A bowl of sour wine stood there. They put a sponge full of the sour wine on a hyssop branch_the same kind of branch the Israelites had to use to sprinkle the lamb's blood on the doorpost, coincidently enough_and held it to his mouth. Before when they offered him wine, what did he do? He refused it: “I will not taste of the fruit of the vine I am coming into the kingdom.” He skipped the fourth cup and then he went to pray, ‘Remove this cup, not as I will will, but as thou wilt,’ And now he has gone and fulfilled that will to the uttermost, in perfect suffering obedience to the Father, in an act of unspeakable love.
“They put a sponge full of the sour wine on hyssop and held it to his mouth. When Jesus had received the sour wine he said the words that are spoken of in the fourth cup consummation, “It is finished.” What is the it referring to? That grammatical question began really bothering me at some point. I asked several people and their response was usually, “Well, it means the work of redemption that Christ was working on.” All right, that's true, I agree it does refer to that, but in context. An exegete, a trained interpreter of the word is supposed to find the contextual meaning, not just import a meaning from a theology textbook. What is Jesus speaking of when he says, “It is finished?” I mean, our redemption is not completed once he - he's not yet raised. Paul says, “He was raised for our justification.”
So what is the it talking about? He said, ‘It is finished’, and he bowed his head and gave up his spirit, his breath. The it, of course you realize by now, is the Passover sacrifice. Because who is Jesus Christ? He is the sacrifice of Egypt, the firstborn son. Remember, the Egyptians involuntarily had to offer up their firstborn sons as atonement for their own sins and wickedness. Christ dies for Egypt and the world. Plus, he is the Passover lamb, the unblemished lamb, without broken bones who offers himself up for the life of the world. This fits with John's gospel, because as soon as Jesus was introduced in chapter 1 of the fourth gospel by John the Baptist, what did John say? He said, “Behold the lamb of God who takes away the sins of the world.” And here is the lamb, headed for the altar of the cross, dying as a righteous firstborn and as an unblemished lamb. I believe that it's best to say in light of scripture that the sacrifice of Christ did not begin with the first spike, it didn't begin when the cross was sunk into the ground. I began in the upper room. That's where the sacrifice began. And I would also suggest that the Passover meal by which Jesus initiated the new Covenant in his own blood did not end in the upper room, but at calvary. It's all of one piece. The sacrifice begins in the upper room with the institution of the Eucharist and it ends at calvary. Calvary begins with the Eucharist. The Eucharist ends at Calvary. But in another way of thinking, it ain't over yet! Cause it ain't over till it's over. Paul tells us in 1 Corinthians 5:7-8, “Christ our Passover lamb has been sacrificed, therefore”_what?_we don't need to have any more sacrifice? Therefore we don't need to have any more ritual, therefore all we have to do is have a personal relationship with Jesus Christ and invite him into our hearts and everything else is taken care of? No, he's too knowledgeable about the Old Testament to say any of that. He says, “Christ our Passover lamb has been sacrificed; let us therefore celebrate the feast.” What feast? The whole Passover feast. It's not complete yet. What do you mean?
Thanks. I agree with the analysis about why Jesus' bones were not broken.
[from the essay:] What is Jesus speaking of when he says, “It is finished?” I mean, our redemption is not completed once he - he's not yet raised. Paul says, “He was raised for our justification.”
I think that's an extremely poor pull quote by the author and is totally out of context. Here is the actual verse:
Rom 4:25 : He was delivered over to death for our sins and was raised to life for our justification.
It wasn't the raising that accomplished our redemption, it was the dying. The raising was PROOF. Paul simply puts the two together in his statement, so there is no justification for saying that "It is finished" means anything other than the completion of redemption.
[Id.] So what is the it talking about? He said, ‘It is finished’, and he bowed his head and gave up his spirit, his breath. The it, of course you realize by now, is the Passover sacrifice.
IMHO, this is the false completion of a false set up. I knew I smelled something coming when the author only quoted half of Paul. :) The Passover sacrifice was not eternal, but temporary. Jesus' sacrifice was eternal and final.
[Id.] The Eucharist ends at Calvary. But in another way of thinking, it ain't over yet! Cause it ain't over till it's over. Paul tells us in 1 Corinthians 5:7-8, “Christ our Passover lamb has been sacrificed, therefore”_what?_we don't need to have any more sacrifice?
For salvation, YES, that is correct. Certainly, Christ is "the lamb" and comparisons can be fairly made. However, I think it's error to compare the sacrifice of Christ to any sacrifice a human might make. Those are two different ballparks. Christ's sacrifice was PERFECT, and had no need to be repeated, unlike the general OT sacrifices. Paul does not say otherwise.
[Id.] Therefore we don't need to have any more ritual, therefore all we have to do is have a personal relationship with Jesus Christ and invite him into our hearts and everything else is taken care of?
For salvation, YES. Christ took care of everything. The alternative is that Christ did not take care of everything and in fact did a half- ............. baked job. :) The author's view has humans needing to clean up after Christ's unfinished business.
The author is wrong in thinking that Christ is merely an ongoing continuation of the paschal lamb sacrifice. (Christians did not partake of that sacrifice after Christ.) Christ is a final, once and for all REPLACEMENT for it. That's what Paul was saying. Leaven should be put away then, and sin should be put away now.