As aChristian, I know that the lamb symbolizes Jesus. Also what a lot of you perhaps do not know, is that the lamb itself was the Egyptian symbol for their God. For the Jews to kill it and eat it in the midst of them was a great insult to them. They bought it on the tenth of the month and they kept it until the 14th of the month. It was an elevation offering. By doing this, God showed His power over their idol.
If you are not a Protestant, but a Catholic, how can you possibly know what goes on in the churches? You have preconceived ideas which really are akin to bigotry and hatred, even xenophobia. (Calvinists here are not openminded either, but mostly they suffer from xzinsphobia.)
Anytime you read a chapter like John 6, good biblical exergesis is to read the whole and try to understand the lesson being taught. John 6:53 is after all that came before it.
There was the feeding of the 5000, and in Mark he makes it plain that the feeding was intended to teach the disciples a lesson which they failed to learn. "Their hearts were hardened" refers to their closed minds, they couldn't understand it.(Mark 6:51-52)The lesson evidently had to do with the person of their Master.
But the further meaning which lies beneath the synoptic record is brought to the surface by John and spelled out in detail. He talks about the bread of life and the manna (John 6:27-34)But Jesus not only gives this bread of life, He is the bread. The bread which He gives is his flesh. (6:51) Now to believe in Christ is not only to give credence to what he says, but it is to be united to him by faith, to participate in his life. It is John's practice when recording Jesus's words or discourses to quote words which have a spiritual meaning and then make the hearers show by their resonse that they failed to grasp that meaning. Jesus answered their protest by pointing out that the words were to be understood spiritually(6:63) Augustine said "Believe, and thou hast eaten". You will notice that the Holy Communion is absent in John but this discourse represents the counterpart to the accounts of what Jesus did and said to the disciples in the upper room. John 6 is not making a direct reference to it but the discourse conveys the same truth in words as the Holy Comunion conveys in action. We take and eat it in remembrance that Christ died for us. And He died once only. We do not want Him humiliated any more, and what you see as Real Presence, we see as Real Presence, for for where a few are gathered together, in His Name, He is there. Now I really must go. Shalom!