Saint John of Damascus Quote

You ask how the bread becomes the Body of Christ, and the wine. . . the Blood of Christ. I shall tell you: the Holy Spirit comes upon them and accomplishes what surpasses every word and thought. . . . Let it be enough for you to understand that it is by the Holy Spirit, just as it was of the Holy Virgin and by the Holy Spirit that the Lord, through and in Himself, took flesh.

-- Saint John of Damascus

Saint Quote: Saint Paul the Apostle On The Holy Eucharist

For as often as you shall eat this bread, and drink the chalice, you shall shew the death of the Lord, until he come.

-- Saint Paul the Apostle from 1 Corinthians 11: 26

Saint Thomas Aquinas (Corpus Christi)

Since it was the will of God’s only-begotten Son that men should share in His divinity, He assumed our nature in order that by becoming man He might make men gods. Moreover, when He took our flesh He dedicated the whole of its substance to our salvation. He offered His body to God the Father on the altar of the cross as a sacrifice for our reconciliation. He shed His blood for our ransom and purification, so that we might be redeemed from our wretched state of bondage and cleansed from all sin. But to ensure that the memory of so great a gift would abide with us for ever, He left His Body as food and His Blood as drink for the faithful to consume in the form of bread and wine.

-- Saint Thomas Aquinas