An image is to the eye what scripture is to the ear

We proclaim Him also by our senses on all sides, and we sanctify the noblest sense, which is that of sight. The image is a memorial, just what words are to a listening ear. What a book is to the literate, that an image is to the illiterate. The image speaks to the sight as words to the ear; it brings us understanding.

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

Those who are against images should keep the whole law

Now, consider the handiwork of man becoming the likeness of the cherubim. How, then, can you make the law a pretence for giving up what it orders? If you invoke it against images, you should keep the Sabbath, and practise circumcision. It is certain that “if you observe the law, Christ will not profit you. You who are justified in the law, you are fallen from grace.”

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

God worked out our salvation through matter

I make an image of the God whom I see. I do not worship matter, I worship the God of matter, who became matter for my sake, and deigned to inhabit matter, who worked out my salvation through matter. I will not cease from honoring that matter which works my salvation.

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

The Cherubim on the Ark were images commanded by God

Answer me this question. Is there only one God? You answer, “Yes, there is only one Law-giver.” Why, then, does He command contrary things? The cherubim are not outside of creation; why, then, does He allow cherubim carved by the hand of man to overshadow the mercy-scat? Is it not evident that as it is impossible to make an image of God, who is uncircumscribed and impassible, or of one like to God, creation should not be worshipped as God. He allows the image of the cherubim who are circumscribed, and prostrate in adoration before the divine throne, to be made, and thus prostrate to overshadow the mercy-seat. It was fitting that the image of the heavenly choirs should overshadow the divine mysteries.

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

Creation is full of images that point to God

If, therefore, Holy Scripture, providing for our need, ever putting before us what is intangible, clothes it in flesh, does it not make an image of what is thus invested with our nature, and brought to the level of our desires, yet invisible? A certain conception through the senses thus takes place in the brain, which was not there before, and is transmitted to the judicial faculty, and added to the mental store. Gregory, who is so eloquent about God, says that the mind, which is set upon getting beyond corporeal things, is incapable of doing it. For the invisible things of God since the creation of the world are made visible through images. (Rom. 1.20) We see images in creation which remind us faintly of God, as when, for instance, we speak of the holy and adorable Trinity, imaged by the sun, or light, or burning rays, or by a running fountain, or a full river, or by the mind, speech, or the spirit within us, or by a rose tree, or a sprouting flower, or a sweet fragrance.

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

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

We make images of Christ who became visible

That flesh is divine, and endures after its assumption. Human nature was not lost in the Godhead, but just as the Word made flesh remained the Word, so flesh became the Word remaining flesh, becoming, rather, one with the Word through union. Therefore I venture to draw an image of the invisible God, not as invisible, but as having become visible for our sakes through flesh and blood. I do not draw an image of the immortal Godhead. I paint the visible flesh of God, for it is impossible to represent a spirit, how much more God who gives breath to the spirit.

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

Christ elevates human nature to godhood

I adore one God, one Godhead but three Persons, God the Father, God the Son made flesh, and God the Holy Ghost, one God. I do not adore creation more than the Creator, but I adore the creature created as I am, adopting creation freely and spontaneously that He might elevate our nature and make us partakers of His divine nature.

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

Church tradition is a faith we carry forward by imitation

A small thing is not small when it leads to something great, nor indeed is it a thing of no matter to give up the ancient tradition of the Church held by our forefathers, whose conduct we should observe, and whose faith we should imitate.

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

 

Man’s free will to sin gives Satan power over him

From which it follows, that in the case of every creature it is a result of his own works and movements, that those powers which appear either to hold sway over others or to exercise power or dominion, have been preferred to and placed over those whom they are said to govern or exercise power over, and not in consequence of a peculiar privilege inherent in their constitutions, but on account of merit.

…Now it is certain that by the dragon is understood the devil himself.  If then they are called opposing powers, and are said to have been once without stain, while spotless purity exists in the essential being of none save the Father, Son, and Holy Spirit, but is an accidental quality in every created thing; and since that which is accidental may also fall away, and since those opposite powers once were spotless, and were once among those which still remain unstained, it is evident from all this that no one is pure either by essence or nature, and that no one was by nature polluted.  And the consequence of this is, that it lies within ourselves and in our own actions to possess either happiness or holiness; or by sloth and negligence to fall from happiness into wickedness and ruin, to such a degree that, through too great proficiency, so to speak, in wickedness (if a man be guilty of so great neglect), he may descend even to that state in which he will be changed into what is called an “opposing power.”

Origen
On First Principles, Book I
Chapter V