Given that context, the subject of an icon is some person such as Christ, Mary the Theotokos (mother or bearer of God), an Old or New Testament figure such as Abraham, the Prophet Elija, or an Apostle, etc., some hero of the Church, such as St. Nicholas or St. Herman of Alaska, or some event from salvation history, such as the the Nativity of Christ, the Resurrection, or an Ecumenical Council. And Iconography is the spiritual art of expressing the spiritual reality of these people and events using sacred symbolic forms and mystical colors.

An icon, in fact, manifests our human participation in the divine through its symbolic pictoral
language. The Incarnation of Christ (God made man, and thus visible) is the theological foundation of the icon which seeks to reveal the divine through visible and familiar content. In this sense, the icon has been called "a meeting between heaven and earth".

The painting (more properly called writing) of icons is a special vocation. The iconographer is expected to fast, pray, and live a holy life so as to be capable of expressing sacred and divine mysteries. Thus the icon becomes, in a way, the fruit of the Holy Spirit, containing spiritual power. Since the 9th Century, the Orthodox Church has established a set of technical rules, or canons for the artistic form of icons. Icons have a very prominent and important place in the worship and piety of the Orthodox Church.

They are deeply rooted in the gospel, and have been cherished and venerated by Christians from the earliest times.