John Chrysostom

"In like manner also the cup after supper, saying, This cup is the New Covenant in My Blood: this do, as oft as ye drink of it, in remembrance of Me."

What sayest thou? Art thou making a remembrance of Christ, and despisest thou the poor and tremblest not? Why, if a son or brother had died and thou wert making a remembrance of him, thou wouldst have been smitten by thy conscience, hadst thou not fulfilled the custom and invited the poor: and when thou art making remembrance of thy Master, dost thou not so much as simply give a portion of the Table?

But what is it which He saith, "This cup is the New Covenant?" Because there was also a cup of the Old Covenant; the libations and the blood of the brute creatures. For after sacrificing, they used to receive the blood in a chalice and bowl and so pour it out. Since then instead of the blood of beasts He brought in His own Blood; lest any should be troubled on hearing this, He reminds them of that ancient sacrifice.