The Holy Scriptures ( The Old Testament, leading to the New Testament ) are a progressive revelation of Christ (Luke 24:27). The Old Testament Scriptures are part of the story of Salvation, and profoundly foretell the incarnation of the Logos. A prime example is the Proto-evangelium. (Genesis 3:15 ) The narratives and characters of the Old Testament point to the coming of Christ, and His ‘new and eternal covenant.’ All manifestations of God in the Old Testament, are of the Word, according to Orthodox exegesis. The main source for Orthodox Christology, is of course the New Testament, where both the Divine and Human natures of Christ are emphasised. We see Christ ‘after fasting for forty days and forty nights..was hungry ( Matthew 4:2 ) and at the same time we read Christ saying ‘Father, the hour has come ; glorify your Son that the Son may glorify..as We are one.’ ( John 17 )
The Early Church was faced with various heresies, and it had to deal with them by affirming the Orthodox Christological position. Arianism was one of the main Christological heresies, ( named after Arius, 256-336 AD ) claiming that the Son of God is created, and separate to God the Father ( Arius claimed that ‘there was a time when the Son was not’ ). Furthermore, Arianism promoted the ideas of Christ’s existence being dependent on God’s will, and that His ‘sonship’ was purely metaphorical. Scripturally, these views were clearly incorrect, therefore the Church had to react to this, and make the holy Orthodox position clear. In the year 325 AD, the First Ecumenical Council ( Council of Nicea ) took place - primarily addressing the problem and rise of Arianism.The Council was summoned by the Emperor Constantine, calling the Church’s Bishops, together in unity - in order to settle the issue at hand. Alexander Schmemann writes that this holy Council was the ‘symbol and crown’ of victory, bringing these heretical ideas (against the Divinity of our Lord and Saviour Christ ) to an end. The Emperor Constantine, in his opening address to the Council emphatically stated that the ‘disputes within the Church are more dangerous than war.. they bring me more grief than anything else.’ The Council of Nicea therefore clarified the holy teachings of the Church: that Jesus Christ is God of very God, begotten before all worlds and not created, and of one essence with the Father ( consubstantial ).
Following this period, several other heresies began to form, questioning Christ’s humanity ( as opposed to Arianism, which questioned the Divinity ). These were Docetism, ( deriving from δοκέω which means to seem ), claiming that the Lord’s humanity was simply an illusion; Nestorianism which was the idea that humanity and divinity could not possibly form unity, and therefore there must have been two separate persons working together; Eutychianism, which put a far greater emphasis on His divinity rather than humanity; and Apollinarianism, claiming that Christ was divine, without a human mind.
For this reason, the Council of Chalcedon ( Fourth Ecumenical Council )in 451 AD, took place. Its purpose was to clarify Christ’s nature ( being fully Divine and fully Human ) rather than the heretical monophysitic views of Jesus having one nature.
Proclamation of the Council :
‘...while Christ is a single, undivided person, He is not only from two natures but in two natures. The bishops acclaimed..the distinction between the two natures is clearly stated, although the unity of Christ's person is also emphasised. In their proclamation of faith they stated their belief in one and the same son, perfect in Godhead and perfect in humanity, truly God and truly human... acknowledged in two natures unconfusedly, unchangeably, indivisibly, inseparably; the difference between the natures is in no way removed because of the union, but rather the peculiar property of each nature is preserved, and both combine in one person and in one hypostasis.’
The council of Chalcedon proclaimed that Christ is indeed perfect in Godhead and manhood, truly God and truly man with a rational body and soul, consubstantial with the Father, without sin. It confirmed the hypostatic union - the two distinct nature, united in One person.