Pseudo-Dionysius: "Most divine of all sacraments"

“Do thou, O holy Sacrament, most divine of all sacraments, lift the veils that envelope Thee with their symbols, reveal Thyself clearly to our sight, and fill the eyes of our mind with a unifying and clear light!”

~Pseudo-Dionysius the Areopagite (6th cent.): Ecclesiastical Hierarchy, 3, 3.

The Institution of the Eucharist, by Joos van Wassenhove.
Oil on wood, 1473-75; Galleria Nazionale delle Marche, Urbino.

Rufinus: God the Father

"That God then is the Father of His only Son our Lord is to be believed, not discussed; for it is not lawful for a servant to dispute about the nativity of his lord. The Father has borne witness from heaven, saying, “This is My beloved Son, in Whom I am well pleased: hear Him.” The Father says that He is His Son and bids us hear Him. The Son says, “He who sees Me sees the Father also,” and “I and the Father are one,” and “I came forth from God and have come into the world.” Where is the man who can thrust himself as a disputant between these words of Father and Son, who can divide the Godhead, separate its volition, break asunder the substance, cut the spirit in parts, and deny that what the Truth speaks is true? God then is a true Father as the Father of the Truth, not begetting extrinsically, but generating the Son from that which Himself is; that is, as the All-wise He generates Wisdom, as the Just Justice, as the Everlasting the Everlasting, as the Immortal Immortality, as the Invisible the Invisible; because He is Light, He generates Brightness, because He is Mind, He generates the Word."

~Rufinus (344–410 A.D.): Commentary on the Apostles' Creed, 4.

Holy Family and God the Father, by Johann Karl Loth.
Oil on canvas, 1681; San Silvestro, Venice.

St. Ambrose: "The heavenly and venerable sacrament"

"THEREFORE dost thou hear that as often as sacrifice is offered, the Lord’s death, the Lord’s resurrection, the Lord’s ascension and the remission of sins is signified, and dost thou not take this bread of life daily? He who has a wound needs a medicine. The wound is that we are under sin; the medicine is the heavenly and venerable sacrament."

~St. Ambrose of Milan (333-397 A.D.): Treatise on the Sacraments, 5, 4, 25.

Institution of the Eucharist, by Fra Angelico.
Fresco, 1441-42; Convento di San Marco, Florence.

St. Augustine: "The sending of the Holy Spirit"

“THIS operation, visibly exhibited, and presented to mortal eyes, is called the sending of the Holy Spirit; not that His very substance appeared, in which He Himself also is invisible and unchangeable, like the Father and the Son, but that the hearts of men, touched by things seen outwardly, might be turned from the manifestation in time of Him as coming to His hidden eternity as ever present.”

~St. Augustine: De Trinitate, 2, 5.

Pentecost, by Sir Anthony van Dyck. Oil on canvas, 1618-20; Staatliche Museen, Berlin.

On St. Justin Martyr

"St. Justin, apologist and martyr, was one of the most important Christian writers of the second century. He himself tells how his study of all the schools of philosophy led him to Christianity, and how he dedicated his life to the defense of the Christian faith as "the one certain and profitable philosophy."

"St. Justin is particularly celebrated for the two Apologies which he was courageous enough to address in succession to the persecuting emperors Antoninus and Marcus Aurelius. One of them contains a description of the rites of baptism and the ceremonies of Mass, thus constituting the most valuable evidence that we possess on the Roman liturgy of his day. He was beheaded in Rome in 165. Justin is also referred to as the Philosopher." ─ catholicculture.org

● Read The First Apology by St. Justin.

Trial of Justin the Philosopher, by Fra Angelico; 1447-1450.

Origen: On Luke 1:46

And Mary said, My soul doth magnify the Lord. (Luke 1:46)

"NOW if the Lord could neither receive increase or decrease, what is this that Mary speaks of, My soul doth magnify the Lord? But if I consider that the Lord our Savior is the image of the invisible God, and that the soul is created according to His image, so as to be an image of an image, then I shall see plainly, that as after the manner of those who are accustomed to paint images, each one of us forming his soul after the image of Christ, makes it great or little, base or noble, after the likeness of the original so when I have made my soul great in thought, word, and deed, the image of God is made great, and the Lord Himself whose image it is, is magnified in my soul."

~Origen Adamantius (184 – 254). Quoted by St. Thomas Aquinas in Cantena Aurea: Gospel of St. Luke.

Visitation, by Mariotto Albertinelli.
Oil on wood, 1503; Galleria degli Uffizi, Florence.

St. Leo the Great: Sermon on the Lord's Ascension (1)

Sermon 73

I. The events recorded as happening after the Resurrection were intended to convince us of its truth

Since the blessed and glorious Resurrection of our Lord Jesus Christ, whereby the Divine power in three days raised the true Temple of God, which the wickedness of the Jews had overthrown, the sacred forty days, dearly-beloved, are today ended, which by most holy appointment were devoted to our most profitable instruction, so that, during the period that the Lord thus protracted the lingering of His bodily presence, our faith in the Resurrection might be fortified by needful proofs. For Christ's Death had much disturbed the disciples' hearts, and a kind of torpor of distrust had crept over their grief-laden minds at His torture on the cross, at His giving up the ghost, at His lifeless body's burial. For, when the holy women, as the Gospel-story has revealed, brought word of the stone rolled away from the tomb, the sepulchre emptied of the body, and the angels bearing witness to the living Lord, their words seemed like ravings to the Apostles and other disciples. Which doubtfulness, the result of human weakness, the Spirit of Truth would most assuredly not have permitted to exist in His own preacher's breasts, had not their trembling anxiety and careful hesitation laid the foundations of our faith. It was our perplexities and our dangers that were provided for in the Apostles: it was ourselves who in these men were taught how to meet the cavillings of the ungodly and the arguments of earthly wisdom. We are instructed by their lookings, we are taught by their hearings, we are convinced by their handlings. Let us give thanks to the Divine management and the holy Father.' necessary slowness of belief. Others doubted, that we might not doubt.

II. And therefore they are in the highest degree instructive

Those days, therefore, dearly-beloved, which intervened between the Lord's Resurrection and Ascension did not pass by in uneventful leisure, but great mysteries were ratified in them, deep truths revealed. In them the fear of awful death was removed, and the immortality not only of the soul but also of the flesh established. In them, through the Lord's breathing upon them, the Holy Ghost is poured upon all the Apostles, and to the blessed Apostle Peter beyond the rest the care of the Lord's flock is entrusted, in addition to the keys of the kingdom. Then it was that the Lord joined the two disciples as a companion on the way, and, to the sweeping away of all the clouds of our uncertainty, upbraided them with the slowness of their timorous hearts. Their enlightened hearts catch the flame of faith, and lukewarm as they have been, are made to burn while the Lord unfolds the Scriptures. In the breaking of bread also their eyes are opened as they eat with Him: how far more blessed is the opening of their eyes, to whom the glorification of their nature is revealed than that of our first parents, on whom fell the disastrous consequences of their transgression.

III. They prove the Resurrection of the flesh

And in the course of these and other miracles, when the disciples were harassed by bewildering thoughts, and the Lord had appeared in their midst and said, Peace be unto you , that what was passing through their hearts might not be their fixed opinion (for they thought they saw a spirit not flesh), He refutes their thoughts so discordant with the Truth, offers to the doubters' eyes the marks of the cross that remained in His hands and feet, and invites them to handle Him with careful scrutiny, because the traces of the nails and spear had been retained to heal the wounds of unbelieving hearts, so that not with wavering faith, but with most steadfast knowledge they might comprehend that the Nature which had been lain in the sepulchre was to sit on God the Father's throne.

IV. Christ's ascension has given us greater privileges and joys than the devil had taken from us

Accordingly, dearly-beloved, throughout this time which elapsed between the Lord's Resurrection and Ascension, God's Providence had this in view, to teach and impress upon both the eyes and hearts of His own people that the Lord Jesus Christ might be acknowledged to have as truly risen, as He was truly born, suffered, and died. And hence the most blessed Apostles and all the disciples, who had been both bewildered at His death on the cross and backward in believing His Resurrection, were so strengthened by the clearness of the truth that when the Lord entered the heights of heaven, not only were they affected with no sadness, but were even filled with great joy. And truly great and unspeakable was their cause for joy, when in the sight of the holy multitude, above the dignity of all heavenly creatures, the Nature of mankind went up, to pass above the angels' ranks and to rise beyond the archangels' heights, and to have Its uplifting limited by no elevation until, received to sit with the Eternal Father, It should be associated on the throne with His glory, to Whose Nature It was united in the Son. Since then Christ's Ascension is our uplifting, and the hope of the Body is raised, whither the glory of the Head has gone before, let us exult, dearly-beloved, with worthy joy and delight in the loyal paying of thanks. For today not only are we confirmed as possessors of paradise, but have also in Christ penetrated the heights of heaven, and have gained still greater things through Christ's unspeakable grace than we had lost through the devil's malice. For us, whom our virulent enemy had driven out from the bliss of our first abode, the Son of God has made members of Himself and placed at the right hand of the Father, with Whom He lives and reigns in the unity of the Holy Spirit, God for ever and ever. Amen.
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Source. Translated by Charles Lett Feltoe. From Nicene and Post-Nicene Fathers, Second Series, Vol. 12. Edited by Philip Schaff and Henry Wace. Buffalo, NY: Christian Literature Publishing Co., 1895.

Ascension of Christ, by Andrea da Firenze. Fresco, 1366-67.
Cappellone degli Spagnoli, Santa Maria Novella, Florence.