The sixth chapter of Isaiah opens with a vision so overwhelming that it defined prophetic experience for all of subsequent Jewish and Christian tradition. In the year that King Uzziah died, the prophet saw the Lord seated on an exalted throne, with the hem of his robe filling the Temple. Above the throne stood the seraphim, six-winged celestial beings whose sustained, antiphonal cry established one of the most important phrases in the entire liturgical tradition: "Holy, holy, holy, is the LORD of hosts: the whole earth is full of his glory."
The Hebrew word seraph comes from a root meaning to burn, and seraphim are the burning ones, beings of fire who stand in the immediate presence of divine holiness. Their six wings serve three purposes: two cover their faces (in the presence of unmediated divine glory), two cover their feet (in an attitude of reverence before the holy), and two enable flight (indicating active service and readiness). The covering of face and feet while remaining in attendance describes a kind of reverential alertness, complete availability combined with the recognition of creaturely limitation before divine majesty.
The Hebrew plural seraphim entered English directly, and seraph became the back-formed singular. Unlike cherubim, which had already developed elaborate iconographic traditions in ancient Near Eastern art and in the decoration of the Ark of the Covenant, seraphim appear only in this one passage in the Hebrew Bible. Their entry into the Christian angelological tradition came through the influence of Pseudo-Dionysius the Areopagite, a sixth-century theologian who wrote an influential treatise on celestial hierarchy. Pseudo-Dionysius assigned seraphim to the highest order of angels, above cherubim and thrones, based on their position in the Isaiah vision immediately surrounding the divine throne.
This hierarchical placement gave seraphim their distinctive status in Western art and literature. Dante placed them in the highest sphere of the Empyrean in the Divine Comedy, surrounding the divine light with their burning love. Medieval theologians associated seraphim specifically with the quality of love or charity, interpreting their burning nature as the intensity of divine love rather than destructive fire. This association made seraphim figures for both the highest mystical union and the most ardent devotional love.
The word entered English poetry as the highest available description of celestial dignity. Milton uses seraphim extensively in Paradise Lost, where they are among the most powerful and most loyal of heaven's servants. Shelley's "Adonais" describes the heaven of the sublime using seraphic imagery. In John Henry Newman's "The Dream of Gerontius," set to music by Elgar, the seraphim appear as the highest order of beings surrounding the divine presence, and their singing echoes Isaiah's trisagion.
The trisagion itself, the three-fold "holy, holy, holy," became the central refrain of Christian liturgy and hymnody. The Sanctus in the Latin Mass derives directly from Isaiah 6:3, fused with the similar acclamation in Revelation 4:8. Reginald Heber's hymn "Holy, Holy, Holy! Lord God Almighty," one of the most sung hymns in Christian history, is essentially an extended meditation on the seraphic acclamation. Every time the Sanctus is sung in a church service, the congregation is re-enacting what the seraphim were doing in Isaiah's vision.
In secular usage, seraphic has become an adjective for a quality of radiant, beatific beauty or benevolence, particularly as expressed in human faces. A seraphic smile is one of otherworldly sweetness and peace. The term is used in biographical and literary description when a face or expression seems to transcend ordinary human expressiveness and suggest something of the divine or angelic. The word thus carries its origin in fire and holiness into contexts of quiet radiance and serene goodness.
The seraphic tradition also influenced the vocabulary of Christian mysticism. The highest states of contemplative union were described in terms borrowed from seraphic imagery: the burning, the direct proximity to divine holiness, the consuming of creaturely self-sufficiency in the fire of divine presence. Pseudo-Dionysius's identification of seraphim with the quality of love specifically associated the burning of the seraphim with the heat of caritas, the divine love that purifies and transforms the soul. Bernard of Clairvaux, Bonaventure, and later Teresa of Avila and John of the Cross all drew on seraphic imagery to describe the highest reaches of contemplative experience.
Francis of Assisi, who received the stigmata on Mount Alverno in 1224, reported a vision of a six-winged seraph in the form of the crucified Christ. This vision, recorded by Bonaventure in his Life of Francis, combined the Isaiah 6 seraphic imagery with the Pauline identification of Christ crucified as the center of Christian life. The seraph-Christ vision became one of the most reproduced images of medieval art, and it established an iconographic tradition in which the highest celestial being and the humiliated suffering servant were identified in a single image.
The word seraphic also entered English as an adjective for a quality of face or expression that suggests otherworldly beauty or serene joy. A seraphic smile is one that transcends ordinary expressiveness; a seraphic countenance suggests the presence of something beyond ordinary human experience. Biographies of saints, mystics, and people of extraordinary goodness reach for the adjective when they want to describe the quality of radiance that seems to exceed what ordinary human happiness explains. The word thus preserves in secular biographical writing a trace of its origin in the burning creatures who stood in the direct presence of divine holiness.