Against the Image
Those who did not approve of the use of icons within the orthodoxy were known as iconoclasts. The iconoclasts' argument regarding images within the church generally surrounds charges of idolatry against the icon. They supported their position in a number of ways.
First, the iconoclasts claimed earthly materials, or "dead matter", could not adequately depict a living thing or divine entity. This incomplete representation, the iconoclasts argued, would direct the attention to visible qualities alone rather than the invisible nature of divinity and is thus considered an idol. Moreover, the iconoclasts were worried about the worshiper's inability to distinguish the image from its prototype and, as a result, risked the worship of creation rather than the creator.
The iconoclasts backed their claims with various Biblical instances in which the use of images and iconography was rejected. Exodus 20:4-5 most plainly forbids the keeping of idols or graven images as part of the Ten Commandments. Additionally, both Moses and Christ are recorded to have disposed of idols, thus further supporting the iconoclasts' authority not only to ban images but to destroy them as well.
In their rejection of the image, the iconoclasts ultimately promoted spiritual worship over iconographic.
Protectors of the Image
In the face of iconoclasm, those in favor of the icon, known as iconophiles, were pressed with creating a defense for the use of iconography. This was risky on their part as iconoclasm not only meant the persecution of the image but of those who sought to protect it as well. By far the person who most defined the defense of the icon was John of Damascus.
In his writings, the Syrian monk appealed to the long-established tradition of iconography within the orthodoxy. Above all, John of Damascus stressed the importance of the incarnation as justification for the figural representation of Christ, arguing that, as humanity is recognizable by their outward appearance, so too is Christ. Figural depictions of Christ are also crucial to the faith, he claimed, as they remind the viewer of the reality of his physical existence on Earth.
John of Damascus not only defended icons of Christ but emphasized the importance of icons of saints as well. He claimed they demonstrated an observable, ideal piety in the form of seemingly everyday individuals. In his defense of the icon, John of Damascus identified the "types" of religious images including: "the presentation of the Father by the Son, God's plan for creation, man as created in God's image and likeness... images prefiguring and typifying what is to come beforehand".
The work of John of Damascus was important in many ways. First and foremost, it presented the first systematic defense of icons during the First Iconoclasm. It is from this argumentation future iconophiles would cite and further develop in later conflicts. Additionally, his careful consideration of the image had effectively created the first comprehensive theory of images within the Byzantine church, a legacy that would endure far beyond iconoclasm.