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