This is my body; this is my blood
On the first day of Unleavened Bread, when the Passover lamb was sacrificed, his disciples said to Jesus, ‘Where do you want us to go and make the preparations for you to eat the passover?’ So he sent two of his disciples, saying to them, ‘Go into the city and you will meet a man carrying a pitcher of water. Follow him, and say to the owner of the house which he enters, “The Master says: Where is my dining room in which I can eat the passover with my disciples?” He will show you a large upper room furnished with couches, all prepared. Make the preparations for us there.’ The disciples set out and went to the city and found everything as he had told them, and prepared the Passover.
And as they were eating he took some bread, and when he had said the blessing he broke it and gave it to them. ‘Take it,’ he said ‘this is my body.’ Then he took a cup, and when he had returned thanks he gave it to them, and all drank from it, and he said to them, ‘This is my blood, the blood of the covenant, which is to be poured out for many. I tell you solemnly, I shall not drink any more wine until the day I drink the new wine in the kingdom of God.’
After psalms had been sung they left for the Mount of Olives.
The Catechism of the Catholic Church
Why Did The Word Become Flesh?
The institution of the Eucharist
1337 The Lord, having loved those who were his own, loved them to the end. Knowing that the hour had come to leave this world and return to the Father, in the course of a meal he washed their feet and gave them the commandment of love. In order to leave them a pledge of this love, in order never to depart from his own and to make them sharers in his Passover, he instituted the Eucharist as the memorial of his death and Resurrection, and commanded his apostles to celebrate it until his return; “thereby he constituted them priests of the New Testament.”
1338 The three synoptic Gospels and St. Paul have handed on to us the account of the institution of the Eucharist; St. John, for his part, reports the words of Jesus in the synagogue of Capernaum that prepare for the institution of the Eucharist: Christ calls himself the bread of life, come down from heaven.
1339 Jesus chose the time of Passover to fulfill what he had announced at Capernaum: giving his disciples his Body and his Blood:
Then came the day of Unleavened Bread, on which the passover lamb had to be sacrificed. So Jesus sent Peter and John, saying, “Go and prepare the passover meal for us, that we may eat it. . . .” They went . . . and prepared the passover. And when the hour came, he sat at table, and the apostles with him. And he said to them, “I have earnestly desired to eat this passover with you before I suffer; for I tell you I shall not eat it again until it is fulfilled in the kingdom of God.”. . . . And he took bread, and when he had given thanks he broke it and gave it to them, saying, “This is my body which is given for you. Do this in remembrance of me.” And likewise the cup after supper, saying, “This cup which is poured out for you is the New Covenant in my blood.”
1340 By celebrating the Last Supper with his apostles in the course of the Passover meal, Jesus gave the Jewish Passover its definitive meaning. Jesus’ passing over to his father by his death and Resurrection, the new Passover, is anticipated in the Supper and celebrated in the Eucharist, which fulfills the Jewish Passover and anticipates the final Passover of the Church in the glory of the kingdom.
“Do this in memory of me”
1341 The command of Jesus to repeat his actions and words “until he comes” does not only ask us to remember Jesus and what he did. It is directed at the liturgical celebration, by the apostles and their successors, of the memorial of Christ, of his life, of his death, of his Resurrection, and of his intercession in the presence of the Father.
1342 From the beginning the Church has been faithful to the Lord’s command. Of the Church of Jerusalem it is written:
They devoted themselves to the apostles’ teaching and fellowship, to the breaking of bread and the prayers. . . . Day by day, attending the temple together and breaking bread in their homes, they partook of food with glad and generous hearts.
1343 It was above all on “the first day of the week,” Sunday, the day of Jesus’ resurrection, that the Christians met “to break bread.” From that time on down to our own day the celebration of the Eucharist has been continued so that today we encounter it everywhere in the Church with the same fundamental structure. It remains the center of the Church’s life.
1344 Thus from celebration to celebration, as they proclaim the Paschal mystery of Jesus “until he comes,” the pilgrim People of God advances, “following the narrow way of the cross,” toward the heavenly banquet, when all the elect will be seated at the table of the kingdom.
Not to us, LORD, not to us but to your name give glory because of your faithfulness and love.
Why should the nations say, “Where is their God?”
Our God is in heaven; whatever God wills is done.
Their idols are silver and gold, the work of human hands.
They have mouths but do not speak, eyes but do not see.
They have ears but do not hear, noses but do not smell.
They have hands but do not feel, feet but do not walk, and no sound rises from their throats.
Their makers shall be like them, all who trust in them.
The house of Israel trusts in the LORD, who is their help and shield.
The house of Aaron trusts in the LORD, who is their help and shield.
Those who fear the LORD trust in the LORD, who is their help and shield.
The LORD remembers us and will bless us, will bless the house of Israel, will bless the house of Aaron,
Will bless those who fear the LORD, small and great alike.
May the LORD increase your number, you and your descendants.
May you be blessed by the LORD, who made heaven and earth.
The heavens belong to the LORD, but the earth is given to us.
The dead do not praise the LORD, all those gone down into silence.
It is we who bless the LORD, both now and forever. Hallelujah!
Source: The New American Bible