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