"This is my blood..., which will be shed for many"
The lovers of this world display their generosity by giving money, clothes and various gifts, but not one of them gives his own blood. Christ gives his. In this way he demonstrates the tenderness he feels for us and his ardent love. Under the Old Law... God consented to receive the blood of sacrifices but this was just to prevent his people from offering it to false gods and, already, this was proof of a very great love. But Christ transformed this rite...; there is no longer the same sacrificial victim; it is himself he offers in sacrifice.
«The bread that we break, is it not a communion in the body of Christ?» (1Cor 10,16)... What is this bread? The body of Christ. What becomes of those who communicate in it? The body of Christ: not a large number of bodies but just one body. Just as this bread, made up of so many wheat grains, makes only one loaf into which the grains disappear - for even though the grains remain in it yet it is impossible to distinguish them in such a closely compact mass - so all of us, together with Christ, make up a single whole... Now, if we all share in the same bread and are united to the same Christ, why don't we show the same love to each other? Why don't we become one in this case too?
This is what was seen at the beginning: «The community of believers was of one heart and mind» (Acts 4,32)... Christ came in search of you who were far away from him to unite himself to you, but you, don't you want to become one with your brother?... You violently separate yourself from him after winning from the Lord so great a proof of his love – and life! For he did not only give his body but, just as our flesh, drawn from the earth, had lost its life and died through sin, so he has introduced, so to speak, another substance like a leaven: this is his body, the body sharing the same nature as ours but free from sin and abounding in life. And he has given it to all of us so that, fed with this banquet of this new food... we might enter immortal life.
St. John Chrysostom (c.345-407), priest at Antioch then Bishop of Constantinople, Doctor of the Church