We do not worship images

We, who are of the faithful, do not worship images as gods, as the heathens did, God forbid, but we mark our loving desire alone to see the face of the person represented in image.

St. John Damascene
Apology Against Those Who Decry Holy Images
Part III, Quoted from St. Athanasius Answers to Antiochus

Solomon’s temple, like the Church, was decorated by images

The temple which Solomon built was consecrated by the blood of animals, and decorated by images of lions, oxen, and the palms and pomegranates. Now, the Church is consecrated by the blood of Christ and of His saints, and it is adorned with the image of Christ and of His saints.

St. John Damascene
Apology Against Those Who Decry Holy Images
Part II

The Lord worked out our salvation through matter

It is not matter which I adore; it is the Lord of matter, becoming matter for my sake, taking up His abode in matter and working out my salvation through matter. For “the Word was made Flesh, and dwelt amongst us.” (Jn. 1.14) It is evident to all that flesh is matter, and that it is created. I reverence and honour matter, and worship that which has brought about my salvation. I honour it, not as God, but as a channel of divine strength and grace.

St. John Damascene
Apology Against Those Who Decry Holy Images
Part II

The intention of those who venerate is what’s important

So with regard to images we must manifest the truth, and take into account the intention of those who make them. If it be in very deed for the glory of God and of His saints to promote goodness, to avoid evil, and save souls, we should receive and honour and worship them as images, and remembrances, likenesses, and the books of the illiterate. We should love and embrace them with hand and heart as reminders of the incarnate God, or His Mother, or of the saints, the participators in the sufferings and the glory of Christ, the conquerors and overthrowers of Satan, and diabolical fraud. If any one should dare to make an image of Almighty God, who is pure Spirit, invisible, uncircumscribed, we reject it as a falsehood. If any one make images for the honour and worship of the Devil and his angels, we abhor them and deliver them to the flames. Or if any one give divine honours to the statues of men, or birds, or reptiles, or any other created thing, we anathematise him.

St. John Damascene
Apology Against Those Who Decry Holy Images
Part II

We honor God by venerating his holy ones

Whenever, then, you see Christians adoring the Cross, know that they are adoring the Crucified Christ, not the mere wood.* If, indeed, they honoured wood as wood, they would be bound to worship trees of whatever kind, as you, O Israel, worshipped them of old, saying to the tree and to the stone, “Thou art my God and didst bring me forth.” (Jer. 2.27) We do not speak either to the Cross or to the representations of the saints in this way. They are not our gods, but books which lie open and are venerated in churches in order to remind us of God and to lead us to worship Him. He who honours the martyr honours God, to whom the martyr bore testimony. He who worships the apostle of Christ worships Him who sent the apostle. He who falls at the feet of Christ’s mother most certainly shows honour to her Son.

St. John Damascene
Apology Against Those Who Decry Holy Images
Quoted from Leo of Neapolis, Against the Jews

There is a difference between worship and veneration

When the Invisible One becomes visible to flesh, you may then draw a likeness of His form. When He who is a pure spirit, without form or limit, immeasurable in the boundlessness of His own nature, existing as God, takes upon Himself the form of a servant in substance and in stature, and a body of flesh, then you may draw His likeness, and show it to anyone willing to contemplate it. Depict His ineffable condescension, His virginal birth, His baptism in the Jordan, His transfiguration on Thabor, His all-powerful sufferings, His death and miracles, the proofs of His Godhead, the deeds which He worked in the flesh through divine power, His saving Cross, His Sepulchre, and resurrection, and ascent into heaven. Give to it all the endurance of engraving and color. Have no fear or anxiety; worship is not all of the same kind. Abraham worshipped the sons of Emmor, impious men in ignorance of God, when he bought the double cave for a tomb. (Gen. 23.7; Acts 7.16) Jacob worshipped his brother Esau and Pharaoh, the Egyptian, but on the point of his staff.* (Gen 33.3) He worshipped, he did not adore. Joshua and Daniel worshipped an angel of God; (Jos. 5.14) they did not adore him. The worship of latreia is one thing, and the worship which is given to merit another.

St. John Damascene
Apology Against Those Who Decry Holy Images
Part I

Exhortation to Deacons and Priests

Exercise the mystery of Christ, O deacons, with purity; therefore, O ministers, do the commands of your Master; do not play the person of a righteous judge; strengthen your office by all things, as learned men, looking upwards, always devoted to the Supreme God.  Render the faithful sacred ministries of the altar to God, prepared in divine matters to set an example; yourselves incline your head to the pastors, so shall it come to pass that ye may be approved of Christ.

Commodianus
Instructions of Commodianus
chapter LXVIII

The rumors spread about early Christian worship

Everywhere also there is mingled among them a certain religion of lust, and they call one another promiscuously brothers and sisters, that even a not unusual debauchery may by the intervention of that sacred name become incestuous:  it is thus that their vain and senseless superstition glories in crimes.  Nor, concerning these things, would intelligent report speak of things so great and various, and requiring to be prefaced by an apology, unless truth were at the bottom of it.  I hear that they adore the head of an ass, that basest of creatures, consecrated by I know not what silly persuasion,—a worthy and appropriate religion for such manners.  Some say that they worship the virilia of their pontiff and priest, and adore the nature, as it were, of their common parent.  I know not whether these things are false; certainly suspicion is applicable to secret and nocturnal rites; and he who explains their ceremonies by reference to a man punished by extreme suffering for his wickedness, and to the deadly wood of the cross, appropriates fitting altars for reprobate and wicked men, that they may worship what they deserve.  Now the story about the initiation of young novices is as much to be detested as it is well known.  An infant covered over with meal, that it may deceive the unwary, is placed before him who is to be stained with their rites:  this infant is slain by the young pupil, who has been urged on as if to harmless blows on the surface of the meal, with dark and secret wounds.  Thirstily—O horror!—they lick up its blood; eagerly they divide its limbs.  By this victim they are pledged together; with this consciousness of wickedness they are covenanted to mutual silence. Such sacred rites as these are more foul than any sacrileges.  And of their banqueting it is well known all men speak of it everywhere; even the speech of our Cirtensian testifies to it.  On a solemn day they assemble at the feast, with all their children, sisters, mothers, people of every sex and of every age.  There, after much feasting, when the fellowship has grown warm, and the fervour of incestuous lust has grown hot with drunkenness, a dog that has been tied to the chandelier is provoked, by throwing a small piece of offal beyond the length of a line by which he is bound, to rush and spring; and thus the conscious light being overturned and extinguished in the shameless darkness, the connections of abominable lust involve them in the uncertainty of fate.  Although not all in fact, yet in consciousness all are alike incestuous, since by the desire of all of them everything is sought for which can happen in the act of each individual.

Minucius Felix
Octavius
Chapter IX

The Eucharist as a sacrifice

We are the true adorers and the true priests, who, praying in spirit, sacrifice, in spirit, prayer,—a victim proper and acceptable to God, which assuredly He has required, which He has looked forward to for Himself! This victim, devoted from the whole heart, fed on faith, tended by truth, entire in innocence, pure in chastity, garlanded with love, we ought to escort with the pomp of good works, amid psalms and hymns, unto God’s altar, to obtain for us all things from God.

Tertullian
On Prayer
Chapter XXVIII