After the same manner also he took the cup, after he had eaten, saying,
This cup is the new testament in my blood: this do you, as often as you drink it, in remembrance of me.
All Commentaries on 1 Corinthians 11:25 Go To 1 Corinthians 11
John Chrysostom
AD 407
Why does Paul mention that the cup is that of the new covenant? Because there was also a cup of the old covenant, which contained the libations and the blood of animals. For after sacrificing, the priests used to catch the blood in a chalice and bowl and then pour it out. But now, instead of the blood of beasts, Christ has introduced his own blood.