Paul makes a point to say that Jesus died for sins on the cross once, for all. Because of this, some people think Catholics believe Jesus dies over & over every time the Mass is said. But the Mass is not a re-sacrifice of Jesus on the cross. Its not a second, third or fourth sacrifice, its "THE" Sacrifice, the re-presentation of the very same one He offered on the cross 2,000 years ago. That sounds a little crazy, doesn't it? But my propensity toward sin is made present daily... My sin is a re-presentation of Adam & Eve's rebellion. It may look different, but at the core, its the same. Christ's Sacrifice may look different because there is no body, no blood, no cross, but at the core, its the same.
In John 6, Jesus said "My flesh is real food & My Blood is real drink"... He was at the synagogue in Capernaum speaking to a crowd of people. The Jews scoffed & grumbled & some of His own disciples walked away. The account seems to imply that only the 12 stuck with Him. This concept of Jesus' flesh & Blood being real food & drink is known to Catholics as the "Real Presence". As we see from this story, many thought the idea was crazy. Cannibalistic. Reprehensible. No self respecting Jew would drink the lifeblood of any creature. Was Jesus speaking figuratively? Why did so many walk away?
I wonder if non-Catholics have trouble with the idea of the Mass as a re-presentation of the original Sacrifice & real presence of Jesus because it simply boggles the mind? It pervades the confines of time & humanity. It seems disgusting to subject someone to torture over & over or to even think of consuming their flesh & blood as sustenance. Its crazy. And that kind of understanding is precisely what caused everyone but the 12 to leave Jesus behind.
So what about me? Do I believe such things? Honestly, I'm still not sure. I know there is something different about the Catholic Eucharist as opposed to a Protestant communion service. I know the peace I feel in the presence of the Blessed Sacrament. But I honestly can't wrap my head around how the Sacrifice of Mass is the very same Sacrifice Jesus offered on the cross. I'm told that as the priest prays, the bread & wine are consecrated to become the Body & Blood of Christ, an "unbloody Sacrifice". The priest is the representative of Jesus to us, essentially Jesus with flesh on. It is Jesus as priest Who consecrates the elements & then presents Himself to us as the Sacrifice, "once, for all". He re-presents the core of His Sacrifice as He says "Do this in remembrance of Me"... "Behold the Lamb of God, Who takes away the sins of the world", none other than the "Body & Blood of Christ"... It truly is a mystery to me.