ca. 96 A.D., Pope Saint Clement, fourth Bishop of Rome, disciple of the Apostles Peter and Paul, Letter to the Corinthians
46:1-5 Brothers, we must follow such examples. For it is written: “Follow the saints, because those who follow them will become saints” (unknown source). Again, it says in another place: “In the company of the innocent, you will be innocent; in the company of the elect, you will be elect; and in a crooked man’s company you will go wrong” (Ps. 18:26-27). Let us, then, follow the innocent and the upright. They, it is, who are God’s elect. …
56:1-4 So we too must intercede for any who have fallen into sin, that considerateness and humility may be granted to them and that they may submit, not to us, but to God’s will. For in that way they will prove fruitful and perfect when God and the saints remember them with mercy. We must accept correction, dear friends. No one should resent it. Warnings we give each other are good and thoroughly beneficial. For they bind us to God’s will. This is what the Holy Word says about it: “The Lord has disciplined me severely and has not given me up to death. For the Lord disciplines the one he loves, and punishes every son he accepts” (Ps. 118:18; Prov. 3:12; Heb. 12:6)."
— ca. 100 A.D., Death of Saint John, the last of the Apostles —
ca. 150 A.D., Hermas, brother of Pope Saint Pius, The Shepherd
3:5:4 [The Shepherd said:] “But those who are weak and slothful in prayer, hesitate to ask anything from the Lord; but the Lord is full of compassion, and gives without fail to all who ask Him. But you, having been strengthened by the holy Angel, and having obtained from Him such intercession, and not being slothful, why do not you ask the Lord for understanding, and receive it from Him?”
ca. 156 A.D., The Martyrdom of Saint Polycarp
17:2-3 [W]e will never be able either to abandon the Christ who suffered for the salvation of the whole world of those who are saved, the blameless on behalf of sinners, or to worship anyone else. For this one, who is the Son of God, we worship, but the martyrs we love as disciples and imitators of the Lord, as they deserve, on account of their matchless devotion to their own King and Teacher. May we also become their partners and fellow disciples!
— Veneration of relics —
18:1-3 The centurion, therefore, seeing the opposition raised by the Jews, set in the middle and cremated [the body], as is their custom. And so later on we took up his bones, which are more valuable than precious stones and finer than refined gold, and deposited them in a suitable place. There gathering together, as we are able, with joy and gladness, the Lord will permit us to celebrate the birthday of his martyrdom in commemoration of those who have already fought in the contest, and for the training and preparation of those who will do so in the future.
19:1-2 Such is the story of the blessed Polycarp. Although he was martyred in Smyrna along with eleven others from Philadelphia, he alone is especially remembered by everyone, so that he is spoken of everywhere, even by pagans. He proved to be not only a distinguished teacher, but also an outstanding martyr, whose martyrdom all desire to imitate, since it was in accord with the pattern of the gospel of Christ. By his endurance he defeated the unrighteous magistrate and so received the crown of immortality; now he rejoices with the apostles and all the righteous, and glorifies the almighty God and Father, and blesses our Lord Jesus Christ, the Savior of our souls and Helmsman of our bodies and Shepherd of the catholic church throughout the world.
ca. 203 A.D., Saint Clement of Alexandria, Stromateis or Miscellanies
7:12 So is [the true Christian] always pure for prayer. He also prays in the society of angels, as being already of angelic rank, and he is never out of their holy keeping; and though he pray alone, he has the choir of the saints standing with him.
203 A.D., Saint Vibia Perpetua and others, earliest-known Christian woman author, The Martyrdom of Saints Perpetua and Felicitas
4:1 [T]he blessed Saturus also has made known this vision of his own, which he has written out with his own hand. “Methought we had suffered [martyrdom], and put off the flesh, and began to be borne toward the east by four angels whose hands touched us not. … And when we were clear of the world below we saw a great light, and I said to Perpetua, for she was by my side: ‘This is what the Lord promised us, we have received His promise.’ And while we were carried by those four angels, we came upon a great open space, which was like as it might be a garden, having rose-trees and all kinds of flowers. … Now there in the garden were certain four angels, more glorious than the others, who when they saw us, gave us honour, and said to the other angels: ‘Lo! they are come; lo! they are come,’ being full of wonder. And those four angels which bare us trembled and set us down, and we crossed on foot a place strewn with violets, where we found Jucundus and Saturninus and Artaxius, who were burned alive in the same persecution, and Quintus who, being also a martyr, had died in prison, and we asked of them where they [i.e., the rest of the martyrs] were. The other angels said unto us: ‘Come first and enter and greet the Lord.’
4:2 “And we came near to a place whose walls were built like as it might be of light, and before the gate of that place were four angels standing, who as we entered clothed us in white robes. And we entered, and heard a sound as of one voice saying: ‘Holy, holy, holy,’ without ceasing (cf. Rev. 4:8). And we saw sitting in the same place one like unto a man white-haired, having hair as white as snow, and with the face of a youth; whose feet we saw not (cf. Rev. 1:14). And on the right and on the left four elders; and behind him were many other elders standing (cf. Rev. 4:4 et al.). And, entering, we stood in wonder before the throne; and the four angels lifted us up, and we kissed Him, and He stroked our faces with His hand. And the other elders said to us: ‘Let us stand.’ And we stood and gave the Kiss of Peace. And the elders said to us: ‘Go and play.’ And I said to Perpetua: ‘You have your wish.’ And she said to me: ‘Thanks be to God, that as I was merry in the flesh, so am I now still merrier here.’”
233 A.D., Origen, disciple of Clement of Alexandria, On Prayer
11:1 It is not only the High Priest who prays with those who truly pray, but also the angels who have joy in heaven upon one sinner that doth penance, more than upon ninety-nine who need not penance (Luke 15:7), and also the souls of the saints who have passed away. This is clear from the case of Raphael offering a rational sacrifice to God for Tobias and Sara. For the Scripture says that after they had prayed, the prayers of them both were heard in the sight of the glory of the great Raphael, and he was sent to heal them both (Tob. 3:16-17). And Raphael himself, in revealing to them his mission to them both, enjoined upon him as an angel by God, says: When thou didst pray now, thou and thy daughter-in-law Sara, I offered the memory of your prayer before the holy one (12:12); and a little further on: I am Raphael, one of the seven angels who bear up the prayers of the saints and enter before the glory of the holy one (12:15; cf. Rev. 8:3-4). …
11:2 Now the one great virtue according to the Word of God is love of one’s neighbour. We must believe that the saints who have died have this love in a far greater degree towards them that are engaged in the combat of life, than those who are still subject to human weakness, and are engaged in the combat along with their weaker brethren.
250 A.D., Saint Cyprian, Bishop of Carthage, Letter to His Clergy
39 [34]:3 Lawrence and Ignatius, though they fought betimes in worldly camps, were true and spiritual soldiers of God; and while they laid the devil on his back with their confession of Christ, they merited the palms and crowns of the Lord by their illustrious passion. We always offer sacrifices for them, as you will recall, as often as we celebrate the passions of the martyrs by commemorating their anniversary day.
ca. 250 A.D., Sub tuum praesidium
— Earliest extant prayer to Mary —
Under your mercy we take refuge, O Mother of God. Do not reject our supplications in necessity, but deliver us from danger, [O you] alone pure and alone blessed.