Christology

Christology is the branch of Christian theology concerned with the person of Jesus Christ — who he is in his divine and human natures, their relationship, and how this bears on his salvific work. The NT presents a high Christology from its earliest layers: Paul's letters (written before the Gospels) identify Jesus with divine titles (Kyrios, Lord; Theos, God), apply OT divine texts to him (Phil. 2:10–11; Rom. 10:13), and present him as the agent of creation and the one through whom God acts cosmically (1 Cor. 8:6; Col. 1:15–17). John's Prologue identifies him as the eternal Logos who was God and became flesh (John 1:1–14). The councils of the 4th–5th centuries hammered out the church's formal Christological definition in response to heresies. Arianism (Jesus is a created being, not fully divine) was condemned at Nicaea (325), which affirmed the Son is homoousios (same substance) with the Father. Apollinarianism (Jesus had a divine mind replacing the human) was condemned at Constantinople (381). Nestorianism (two persons in Christ) and Eutychianism (two natures merged into one) were condemned at Chalcedon (451), which defined Christ as one person in two natures, fully divine and fully human, without confusion, change, division, or separation — the formula that has defined orthodox Christology ever since.