Christ connected Himself to the Paschal lamb. In order for the Israelites to escape the final plague, they had to kill a yearling lamb on Nisan 14, smear its blood on their doorposts, and eat the lamb. After they were freed God told them to keep the memorial of that moment, that is, to make it present. The Eucharist is the Pasch of the New Covenant. Christ is not crucified again, but we are allowed to participate in His Sacrifice.
This why Paul says:
15 I am speaking as to sensible people; judge for yourselves what I am saying. 16 The cup of blessing that we bless, is it not a participation in the blood of Christ? The bread that we break, is it not a participation in the body of Christ? 17 Because the loaf of bread is one, we, though many, are one body, for we all partake of the one loaf.
18 Look at Israel according to the flesh; are not those who eat the sacrifices participants in the altar? 19 So what am I saying? That meat sacrificed to idols is anything? Or that an idol is anything? 20 No, I mean that what they sacrifice, [they sacrifice] to demons,[a] not to God, and I do not want you to become participants with demons. 21 You cannot drink the cup of the Lord and also the cup of demons. You cannot partake of the table of the Lord and of the table of demons.
And in Hebrews:
9
Do not be carried away by all kinds of strange teaching.* It is good to have our hearts strengthened by grace and not by foods, which do not benefit those who live by them.g
10
We have an altar* from which those who serve the tabernacle have no right to eat.