John of Damascus

God became man so that man might become God by grace. Or as St John of Damascus put it:

I do not worship the creation rather than the Creator, but I worship the one who became a creature, who was formed as I was, who clothed Himself in creation without debasement or departing from His divinity, that He might raise my nature in glory and make it a partaker of His divine nature.

This explains why we have icons of holy people as well as of Christ. In the saint we see Christ shining forth. We worship God alone, but we venerate and honour all those people and things through which God comes to us.

Deification, or transfiguration as it may be termed, also explains the characteristic style of icons. The way an icon is painted suggests a world shining with the glory of God. It is not just what is depicted that is significant about the icon tradition, but how this is depicted. It is possible to depict a holy person in a profane way, omitting to suggest their transfigured state. Conversely, one can depict a mundane object in a sacred way, showing it in its paradisiacal state.

Deification is the norm that God intended for man, and so a naturalistic portrait, as wonderful and sympathetic as it might be in a painting, is not actually depicting man in his full and ‘natural’ supra-natural state.

Aidan Hart, Techniques of Icon and Wall Painting, 3.

And through the invocation the overshadowing power of the Holy Ghost becomes a rainfall for this new cultivation. For just as all things whatsoever God made he made by the operation of the Holy Ghost, so also it is by the operation of the Spirit that these things are done which surpass nature and cannot be discerned except by faith alone. “How shall this be done to me,” asked the blessed Virgin, “because I know not a man?” The archangel Gabriel answered, “The Holy Ghost shall come upon you, and the power of the Most High shall overshadow you.” And now you ask how the bread becomes the body of Christ and the wine and water the blood of Christ. And I tell you that the Holy Ghost comes down and works these things which are beyond description and understanding.

John of Damascus, Orthodox Faith 4.13, quoted in Arthur A Just (ed), Luke, Ancient Christian Commentary on Scripture, New Testament III, (Intervarsity Press, 2003) 19.