“God rests in holy places: that is, the Theotokos, and all the saints. These are they who have become likenesses of God as far as is possible, since they have chosen to cooperate with divine election. Therefore God dwells in them. They are truly called gods, not by nature, but by adoption, just as red-hot iron is called fiery, not by its nature, but because it participates in the action of the fire…We are God’s temple and the Spirit of God dwells in us…Therefore, since they are truly gods, not by nature, but because they partake of the divine nature, they are to be venerated, not because they deserve it on their own account, but because they bear in themselves Him who is by nature worshipful.” Saint John of Damascus
The 7th Ecumenical Council took place in Nicea in 787 AD. This last of the Ecumenical Councils dealt with icons.
The Council’s Teaching: Concerning the teaching of icons
Venerating icons, having them in churches and homes, is what the Church teaches. They are “open books to remind us of God.” Those who lack the time or learning to study theology need only to enter a church to see the mysteries of the Christian religion unfolded before them.
Concerning the doctrinal significance of icons
Icons are necessary and essential because they protect the full and proper doctrine of the Incarnation. While God cannot be represented in His eternal nature (“…no man has seen God”, John 1:18), He can be depicted simply because He “became human and took flesh.” Of Him who took a material body, material images can be made. In so taking a material body, God proved that matter can be redeemed. He deified matter, making it spirit-bearing, and so if flesh can be a medium for the Spirit, so can wood or paint, although in a different fashion.
I do not worship matter, but the Creator of matter, who for my sake became material and deigned to dwell in matter, who through matter effected my salvation… —St. John of Damascus
The seventh and last Ecumenical Council upheld the iconodules’ postion in AD 787. They proclaimed: Icons… are to be kept in churches and honored with the same relative veneration as is shown to other material symbols, such as the ‘precious and life-giving Cross’ and the Book of the Gospels. The ‘doctrine of icons’ is tied to the Orthodox teaching that all of God’s creation is to be redeemed and glorified, both spiritual and material.