The Eucharist is the Lord's Passover

A treatise by St Gaudentius of Brescia

One man has died for all, and now in every church in the mystery of bread and wine he heals those for whom he is offered in sacrifice, giving life to those who believe and holiness to those who consecrate the offering. This is the flesh of the Lamb; this is his blood. The bread that came down from heaven declared: The bread that I will give is my flesh for the life of the world. It is significant, too, that his blood should be given to us in the form of wine, for his own words in the gospel, I am the true vine, imply clearly enough that whenever wine is offered as a representation of Christ's passion, it is his blood. This means that it was of Christ that the blessed patriarch Jacob prophesied when he said: He will wash his tunic in wine and his cloak in the blood of the grape. The tunic was our flesh, which Christ was to put on like a garment and which he was to wash in his own blood.
Creator and Lord of all things, whatever their nature, he brought forth bread from the earth and changed it into his own body. Not only had he the power to do this, but he had promised it; and, as he had changed water into wine, he also changed wine into his own blood. It is the Lord's passover, Scripture tells us, that is, the Lord's passing. We are no longer to look upon the bread and wine as earthly substances. They have become heavenly, because Christ has passed into them and changed them into his body and blood. What you receive is the body of him who is the heavenly bread, and the blood of him who is the sacred vine; for when he offered his disciples the consecrated bread and wine, he said: This is my body, this is my blood. We have put our trust in him. I urge you to have faith in him; truth can never deceive.
When Christ told the crowds that they must eat his flesh and drink his blood, they were horrified and began to murmur among themselves: This teaching is too hard; who can be expected to listen to it? As I have already told you, thoughts such as these must be banished. The Lord himself used heavenly fire to drive them away be going on to declare: It is the spirit that gives life; the flesh is of no avail. The words that I have spoken to you are spirit and life.

Saint Gaudentius of Brescia (d. 410) was a native of Brescia, Italy, and studied under Saint Philastrius there. He went on pilgrimage to Jerusalem and then became a monk at Caesarea in Cappadocia. He was elected to succeed Philastrius as bishop of Brescia, despite his own objections, and was consecrated by St. Ambrose about 387. Gaudentius wrote many pastoral letters, and ten of his sermons have come down to us. They show his desire to educate his listeners, and present them with good examples for living.
He was one of three bishops sent by Pope Innocent I and Emperor Honorius to Constantinople to defend St. John Chrysostom before Emperor Arcadius in 405. The bishops were imprisoned in Thrace and were offered bribes in an unsuccessful attempt to get them to denounce Chrysostom. Eventually, they were freed and forced to return to Italy. They were put on a ship but their ship sank near Lampsacus. They eventually reached home safely. Gaudentius brought back many precious relics of St. John Baptist. of the Apostles and of the Forty Martyrs of Sebaste. These he received at Caesarea in Cappadocia from nieces of St. Basil. Gaudentius was known for his oratory and exemplary life. He died of natural causes in Italy in 410.