Just as the senses can neither grasp nor perceive the things of the mind, just as representation and shape cannot take in the simple and the shapeless, just as corporal form cannot lay hold of the intangible and incorporeal, by the same standard of truth beings are surpassed by the infinity beyond being, intelligences by that which is beyond intelligence.

Indeed the inscrutable One is out of the reach of every rational process. Nor can any words come up to the inexpressible Good, this One, this Source of all unity, this supra-existent Being. Mind beyond mind, word beyond speech, it is gathered up by no discourse, by no intuition, by no name. It is and it is as no other being is. Cause of all existence, and therefore itself transcending existence, it alone could give an authoritative account of what it really is.

Pseudo-Dionysius the Areopagite, On the Divine Names, 1-1

When we hear the word "spirit" it is impossible for us to conceive of something whose nature can be circumscribed or is subject to change or variation, or is like a creature in any way

Instead, we are compelled to direct our thoughts on high, and to think of an intelligent being, boundless in power, of unlimited greatness, generous in goodness, whom time cannot measure.

All things thirsting for holiness turn to Him; everything living in virtue never turns away from Him. He waters them with His life-giving breath and helps them reach their proper fulfillment.

He perfects all other things, and Himself lacks nothing; He gives life to all things, and is never depleted. He does not increase by additions, but is always complete, self-established, and present everywhere.

He is the source of sanctification, spiritual light, who gives illumination to everyone using His powers to search for the truth – and the illumination He gives is Himself.

His nature is unapproachable; only through His goodness are we able to draw near it. He fills all things with His power, but only those who are worthy may share it. He distributes His energy in proportion to the faith of the recipient, not confining it to a single share.

He is simple in being; His powers are manifold: they are wholly present everywhere and in everything. He is distributed but does not change. He is shared, yet remains whole.

St Basil the Great, On the Holy Spirit, 22

These things having learnt, and being fully persuaded that what seems bread is not bread, though bread by taste, but the Body of Christ; and that what seems wine is not wine, though the taste will have it so, but the Blood of Christ; and that of this David sung of old, saying, And bread which strengtheneth man's heart, and oil to make his face shine (Ps.104:15), 'strengthen thine heart', partaking thereof as spiritual, and 'make the face of thy soul to shine'.

And so having it unveiled by a pure conscience, mayest thou behold as in a glass the glory of the Lord, and proceed from glory to glory (2Co. 3:18), in Christ Jesus our Lord.

St Cyril of Jerusalem, Mystagogical Catechesis IV

Now turn from the ancient to the recent, from the figure to the reality. There we have Moses sent from God to Egypt; here, Christ, sent by His Father into the world: there, that Moses might lead forth an oppressed people out of Egypt; here, that Christ might rescue mankind who are whelmed under sins: there, the blood of a lamb was the spell against the destroyer: here, the blood of the unblemished Lamb Jesus Christ is made the charm to scare evil spirits: there, the tyrant pursued even to the sea that ancient people; and in like manner this daring and shameless spirit, the author of evil, followed thee, even to the very streams of salvation. The tyrant of old was drowned in the sea; and this present one disappears in the salutary water.

St Cyril of Jerusalem, Mystagogical Catechesis I

When the Lord says to the leper who was cleansed, Go, show yourself to the priest and offer the gift for your cleansing, as Moses commanded, in testimony to them (Lk 5:14), he seems to approve of the sacrifice that was commanded by Moses, although the Church has not accepted it.

He can be understood to have ordered this because the sacrifice, the holy of holies, which is his body, had not yet begun, for he had not yet offered his holocaust in his passion. When that sacrifice was established among the believing people, the Temple was overthrown in which those sacrifices were customarily offered. This happened in accordance with the prophecy of Daniel.

For it was not appropriate to abolish the sacrifices that signified it before the sacrifice that they signified was established through the testimony of the apostles who preached it and the faith of the people who believed them.

St Augustine, Questions on Luke's Gospel, Q3

Shun schisms, as the source of troubles. Let all follow the bishop as Jesus Christ did the Father, and the priests, as you would the Apostles. Reverence the deacons as you would the command of God. Apart from the bishop, let no one perform any of the functions that pertain to the Church. Let that Eucharist be held valid which is offered by the bishop or by one to whom the bishop has committed this charge. Wherever the bishop appears, there let the people be; as wherever Jesus Christ is, there is the Catholic Church. It is not lawful to baptize or give communion without the consent of the bishop. On the other hand, whatever has his approval is pleasing to God. Thus, whatever you do will be safe and valid.

St Ignatius of Antioch, Epistle to the Smyrnaeans, 8

Ignatius Theophorus to the Church on which the majesty of the most high Father and of Jesus Christ, His only Son, has had mercy; to the Church beloved and enlightened by the faith and charity of Jesus Christ, our God, through the will of Him who has willed all things that exist–the Church in the place of the country of the Romans which holds the primacy.

I salute you in the name of Jesus Christ, the Son of the Father. You are a Church worthy of God, worthy of honor, felicitation and praise, worthy of attaining to God, a Church without blemish, which holds the primacy of the community of love, obedient to Christ's law, bearing the Father's name. To you who are united, outwardly and inwardly, in the whole of His commandment and filled with grace, in union with God and with every alien stain filtered away, I wish every innocent joy in Jesus Christ, our God.

St Ignatius of Antioch, Epistle to the Romans (emphasis added)

Come together in common, one and all without exception in charity, in one faith and in one Jesus Christ, who is of the race of David according to the flesh, the son of man and Son of God, so that with undivided mind you may obey the bishop and the priests, and break one Bread which is the medicine of immortality and the antidote against death, enabling us to live for ever in Jesus Christ.

St Ignatius of Antioch, Epistle to the Ephesians, 20

While we are yet on earth, let us repent. For we are as clay for the hand of the workman. Just as the potter, if he makes a vessel and it bends or breaks in his hands, shapes it over again, but if he has gone so far as to put it into the fiery oven, can do nothing to help it any more; so let us also, while we are still in this world, repent with our whole heart of the evil things we have done in the flesh, that we may be saved by the Lord while we have time for repentance.

For, after leaving the world, we cannot there confess or repent any more. So then, brothers, by doing the will of the Father and preserving the flesh pure and keeping the commandments of the Lord, we shall obtain eternal life.

Pseudo-Clement of Rome, Second Epistle to the Corinthians, 8

Enquiring then what was the source of my judgment, when I did so judge I had discovered the immutable and true eternity of truth above my changing mind.

Thus by stages I passed from bodies to the soul which uses the body for its perceiving, and from this to the soul's inner power, to which the body's senses present external things, as indeed the beasts are able; and from there I passed on to the reasoning power, to which is referred for judgment what is received from the body's senses.

This too realised that it was mutable in me, and rose to its own understanding. It withdrew my thought from its habitual way, abstracting from the confused crowds of phantasms that it might find what light suffused it, when with utter certainty it cried aloud that the immutable was to be preferred to the mutable, and how it had come to know the immutable itself: for if it had not come to some knowledge of the immutable, it could not have known it as certainly preferable to the mutable. Thus in the thrust of a trembling glance my mind arrived at That Which Is.

St Augustine, Confessions, VII-XVII