The Chalcedonian Definition was adopted at the Council of Chalcedon in AD 451. Many of the prominent heresies of that time challenged the orthodox understanding of Jesus’ nature, claiming that He was something other than what the Scriptures showed Him to be. The Nestorians taught that Jesus was two persons (one human and one divine) in one body. The Apollinarians taught that Jesus had a human body and soul, but that a divine mind had inhabited this, making Him become Christ. The Eutychians taught that Jesus’ human and divine natures fused into a third nature that was not quite either of the other two. Docetists taught that Jesus was truly God but only appeared to be human. And the Arians continued to teach that Jesus was not quite fully God. Each of these heresies, and others like them, had serious implications on the way we understand the Gospel. For that reason, orthodox leaders gathered and crafted this creed as a clear statement on the nature of Jesus.
Following the holy fathers, all with one consent, we teach men to confess one and the same Son, our Lord Jesus Christ, Who is perfect in His deity and also perfect in His humanity.
He is truly God and truly man, having a rational soul and body.
He is consubstantial with the Father in deity and consubstantial with us in humanity.
In all things, He is like unto us, but without sin.
Before all ages, He is begotten of the Father, according to His godhood.
And in these latter days, for us and for our salvation, He was born of the virgin Mary, the mother of God, according to His manhood.
He is One and the same Christ, Son, Lord, Only-Begotten, Who should be acknowledged in two natures, which are unmistakable, unchangeable, indivisible, and inseparable.
The distinction between the natures is not removed by their union, but the property of each nature is preserved, concurring in one Person and one subsistence.
His nature is not parted or divided into two persons, but one and the same Son, the Only-Begotten.
He is God the Word, the Lord Jesus Christ, as the prophets have declared from the beginning concerning Him, as the Lord Jesus Christ Himself has taught us, and as the creed of the holy fathers has handed down to us.