The key tenant to the Christian faith is indeed the Incarnation, as in the Incarnation is bound the death, burial and resurrection of Jesus Christ. As Paul wrote to the church at Philipi, he wrote something, or rehearsed something into print, that has stuck with the Church, and in the hearts and minds of the Saints, for the last two thousand years.
For there is born to you this day in the city of David a Savior, who is Christ the Lord. (Luke 2:11 NKJV)
It is too simply said that for the child to have been born already Christ the Lord, then more than a measure of preexistence must be. We know that in the beginning the Word existed, and further that the Word was God having spoken or God in Actions, and thus no separate deity, and no lesser God. It is the nature of the Incarnation – Deity or Created – that still separates some. It is also the very divine nature of the Incarnation that provides for us a common ground, a foundation for discussion on the Godhead itself.
Your attitude should be the same that Christ Jesus had:
Though he was God, he did not demand and cling to his rights as God. He made himself nothing; he took the humble position of a slave and appeared in human form. And in human form he obediently humbled himself even further by dying a criminal’s death on a cross. (Philippians 2:5-8 NLT)
That mystery the Jews traduce, the Greeks deride, but we adore; and your own love and devotion to the Word also will be the greater, because in His Manhood He seems so little worth.
Although Trinitarian, Athanasius is correct here, and the more so because of his long battles against the Arians.
Ignatius of Antioch, the great bishop of that city, wrote long before Athanasius,
There is one Physician who is possessed both of flesh and spirit; both made and not made; God existing in flesh; true life in death; both of Mary and of God; first possible and then impossible, — even Jesus Christ our Lord.
Where is the boasting of those who are styled prudent? For our God, Jesus Christ, was, according to the economy of God, conceived in the womb by Mary, of the seed of David, but by the Holy Ghost. He was born and baptized, that by His passion He might purify the water. – Epistle to the Ephesians
In each of Ignatius’ seven letters that have been preserved, he calls Jesus Christ God,
Ephesians:“Ignatius … to the Church which is at Ephesus, … united and elected through the true passion by the will of the Father, and Jesus Christ, our God” (Proem.)
“Being the followers of God, and stirring up yourselves by the blood of God, ye have perfectly accomplished the work which was beseeming to you”. (ch.1)
“Jesus Christ, who was of the seed of David according to the flesh, being both the Son of man and the Son of God…” (ch.20)
Do ye therefore all run together as into one temple of God, as to one altar, as to one Jesus Christ, who came forth from one Father, and is with and has gone to one. (Ch. 7)
“Jesus Christ is in the place of all that is ancient: His cross, and death, and resurrection, and the faith which is by Him…” (Ch. 8)
“…I pray for your happiness for ever in our God, Jesus Christ, …” (Ch. 8)
“Ignatius, who is also called Theophorus, to the Church which has obtained mercy, through the majesty of the Most High Father, and Jesus Christ, His only-begotten Son; the Church which is beloved and enlightened by the will of Him that willeth all things which are according to the love of Jesus Christ our God, which … is named from Christ, and from the Father, which I also salute in the name of Jesus Christ, the Son of the Father: to those who are united, both according to the flesh and spirit, to every one of His commandments; who are filled inseparably with the grace of God, and are purified from every strange taint, abundance of happiness unblameably, in Jesus Christ our God.” (Proem)
“I Glorify God, even Jesus Christ, … He was truly of the seed of David according to the flesh, and the Son of God according to the will and power of God; that He was truly born of a virgin, was baptized by John, in order that all righteousness might be fulfilled by Him; and was truly, under Pontius Pilate and Herod the tetrarch, nailed for us in His flesh. Of this fruit we are by His divinely-blessed passion, that He might set up a standard for all ages, through His resurrection, to all His holy and faithful , whether among Jews or Gentiles, in the one body of His Church.” (Ch. 1)
“Now, He suffered all these things for our sakes, that we might be saved. And He suffered truly, even as also He truly raised up Himself, not, as certain unbelievers maintain, that He only seemed to suffer, as they themselves only seem to be .” (Ch. 2)
“For I know that after His resurrection also He was still possessed of flesh, and I believe that He is so now. When, for instance, He came to those who were with Peter, He said to them, “Lay hold, handle Me, and see that I am not an incorporeal spirit.” And immediately they touched Him, and believed, being convinced both by His flesh and spirit. For this cause also they despised death, and were found its conquerors. And after his resurrection He did eat and drink with them, as being possessed of flesh, although spiritually He was united to the Father.” (Ch. 3)
“Stop your ears, therefore, when any one speaks to you at variance with Jesus Christ, who was descended from David, and was also of Mary; who was truly born, and did eat and drink. He was truly persecuted under Pontius Pilate; He was truly crucified, and died, in the sight of beings in heaven, and on earth, and under the earth. He was also truly raised from the dead, His Father quickening Him, even as after the same manner His Father will so raise up us who believe in Him by Christ Jesus, apart from whom we do not possess the true life.” (Ch. 9)
“But if, as some that are without God, that is, the unbelieving, say, that He only seemed to suffer (they themselves only seeming to exist), then why am I in bonds? Why do I long to be exposed to the wild beasts? Do I therefore die in vain? Am I not then guilty of falsehood against the Lord?” (Ch. 10)
From the first generation after the Apostles, on who are great men such as Polycarp (to all under heaven who shall believe in our Lord and God Jesus Christ and in his Father who raised him from the dead.” (Ch. 12) and our Ignatius, there is the very doctrine that it was God in the flesh (in carne – Latin, in the flesh). It was to them the central doctrinal point, and one that would cause doctrinal discussions until even our modern times. What is the nature of the Incarnation?
It is well said that without the Incarnation there is no Christianity, and with no true Christianity, no Christian. This shared faith of ours, this very path to eternal life, is based on the premise that a sacrifice was needed in order to restore the human ability to have not only fellowship, but a relationship with God, just as in Eden before Time. The Scriptures presents the history and future of humanity as having begun in a Garden in which we would walk and talk with the Lord God and because of our sin in Adam, we were separated from God, but there will come a time in the future that Humanity will be given that chance one more, but it all hinges on that sacrifice. Christ must be Deity in order for the Sacrifice of the Cross to be efficacious, for human sins to be “removed” and/or “conquered”.
Arianism, ancient and modern, would have us demote Christ to some secondary being or to some adopted Son, removing from Him that immanent deity and replacing it with a lesser divinity either gained or created. By doing this, there is the notion that Christ was suddenly created, thrown into existence and thus the Incarnation was not Christ coming in the flesh, but instead being created.
The Incarnation expresses first love and then obedience, or perhaps obedience because of love. Without it, and with Arianism, you have only a created sacrifice of only forced obedience without love. Paul writes, perhaps borrowing from an earlier hymn, that the living God thought more of humanity and His creation than He did of His deity and willingly gave it up. He robed Himself with the flesh of humanity (Galatians 4.4) being born of a woman, being made subject to the law, that is sin, thus we return here to the idea that God was a slave, that is to those same mortal coil that we share, you and I.
The setting of a garden provides for us a setting to test obedience. In Eden, God told Adam have it all, except for one fruit of a certain tree. He was disobedient. In Gethsemane, Christ is pictured in the throws of anguish, with his sweat becoming as great drops of blood, which as been pointed to as a sign for physical duress. Here is our Lord in the flesh who became a slave to sin, walking in humility for over three decades, teaching, preaching, and serving – in His our of need, when His soul was abundantly sorrowful – He prayed that His cup would pass from Him. Could Christ have walked away from us, leaving His creation to suffer the pains of death without God?
Did He have that right?
Indeed, for His creation had been disobedient, His people has repeatedly turn from Him to worship other gods, and now, one of His closest friends, along with the Roman Empire, were on the way to betray Him. Yet, the love that first caused His obedience is what He succumbed to and what He would give His life for, but without the Incarnation – and the preexistence that it requires – there is no obedience and thus no love, only a duty and a requirement. There is no true sacrifice, but an offering.
All of those that attribute deity to Christ find that the Incarnation is the essence of Christianity – He was more than a good man, a prophet, a created being – He was and is God. The doctrine of the purpose of the Atonement, or perhaps the ability of the Atonement, is secondary to the Doctrine of the Incarnation itself, which must first be correct so that the others may align.