Sorry if the title sounds confusing or if my prose gets a little hazy, I'm staring at my mixing bowl and contemplating whether in the next little while if it will be put to good use. But the title will make sense momentarily.
Here's what I'm arguing today: The Eucharist is really Jesus, not just symbolic, because of the Old Testament Torah. In other words, Jesus is the final fulfillment of the sacrifices that were taking place at the Temple.
This bread is my flesh which I will give for the life of the world.
If you've read any of the Torah, you will realize that there are sections devoted to ritual sacrifice. Generally speaking a person brings in the first fruits of their harvest, they bring in a sacrifice for a first born son, or they offer a sacrifice for their sins. Depending on reason for the sacrifice, the offering is burnt upon the altar by a priest. If it is an animal the animal will be slaughtered and the blood will be sprinkled upon the altar and then the animal fat burnt. The rest of the animal will be cooked to feed the priests. In other words, once the sacrifice has been carried out, the priests eat the flesh. In certain sacrifices only the priest can eat the sacrifice.
I imagine God's reason behind feeding the Levites in this way was because the Levites were the only clan allowed to perform these rituals and they were responsible for the Temple. Levites especially those serving as priests didn't farm or raise live-stock (although they did receive compensation in the form of tithing). Therefore, the only way they could eat would be through the other tribes of Israel or the sacrifices made at the Temple. As such, the sacrifices held double significance: 1) to fulfill whatever obligation the Israelite had and 2) to feed the priest.
In keeping with this, Jesus, the Sacrificial Lamb, had to spill his blood for the sins of others. And once his sacrifice was over his flesh had to be eaten. We also consume his blood, which incidentally is against Torah teaching. So is eating a man's flesh for that matter. You can see the early followers of Jesus had a real problem with this because it sounded both crazy and was blasphemous. John 6:55 From this time many of his disciples turned back and no longer followed him.
I ague that Jesus's sacrifice would be for nothing if he did not give his flesh to the priesthood. He often spoke of being the bread of life and manna from heaven. He meant that he would nourish our spirituality and feed our souls. This is in keeping with the Torah sacrifices' two purposes. In other words, it makes perfect sense why Jesus said to "eat my flesh" because that is exactly what he wanted us to do in order to complete the Torah codes of ritual sacrifice.
If I haven't said this before, the Catholic church has two priesthoods: the priesthood of men who perform the sacraments, church services, etc. and the priesthood of man who are all baptized persons. Jesus could have made his flesh special only for the religious priesthood, but he opened himself to be partaken by the priesthood of man.
Because Catholic consider his flesh to be sacred, we don't allow just anyone to take part in communion. You must be a Catholic who has gone through 1st Communion classes, which basically teaches you and makes sure that you understand that the Holy Eucharist is indeed Jesus and not symbolic. Persons who are severely mentally disabled cannot partake if they don't understand, Catholics who do not believe in the Real Presence ie that the Consecrated Host is Jesus cannot partake, and other Christians who do not follow the authority of the Catholic Church cannot partake. It's a limited priesthood, just like the Levites.
Another thing to point out is that Catholics base a lot of our beliefs on the New Testament being a fulfillment or completion of the Old Testament covenants. Jesus, as our Sacrificial Lamb, is a completion and reparation for our sins. His flesh is also life saving, and we must eat it.