I do not fully understand all that the incarnation of Christ encompasses. What is clearly taught from scripture is that Jesus was and is both fully God and fully man (Colossians 2:9). In order to procure our redemption, He had to become a man subject to human frailties (He got hungry and needed to eat; He got sleepy and needed to sleep; He grew fatigued and needed to rest, for example), but in His humanity also existed His full deity. He was without sin in His perfection, and He could not sin in His humanity because of His deity.
God the Son had to die as a man in order to qualify Him to pay the infinite price (wages of sin) incurred by all mankind as a result of Adam’s fall. The first Adam was created without sin; but because he (as all created things are) was a created being and thus not divine, Adam and Eve had the capacity to sin, and of course, they did.
God created them perfect, but gave to them the freedom of will to choose obedience or rebellion. Adam, of course, chose rebellion. Jesus – the eternally existent One (Revelation 1:8; 22:13-21), God the Son, incarnated into human flesh, at Bethlehem was born as the 2nd Adam – both fully human and fully divine.
This uniqueness of being qualified Him to live the perfect sinless life, never sinning in thought, word, or deed. Being a divine human God-Man thus qualified Him alone to pay the penalty, the righteous justice that holy God demanded as an atonement for the sin-curse under which all of humanity is born guilty (Romans 3:23; 6:23). Because of Adam’s rebellion, mankind needed a Savior. Only God alone could be that Savior.
It was not Jesus’ physical suffering, as great as it was, that paid in full the sin-debt of mankind. No, it was that instant when Jesus “became sin” for all humanity – when God “laid on Him (Jesus) the iniquity of us all” (Isaiah 53).
When Jesus from the cross cried aloud, “It is finished!” all that ever needed to be done to accomplish the eternal redemption of fallen man was finished and completed in that instant. The doctrine that one can lose one’s salvation negates Christ’s finished work for the salvation of all mankind at Calvary, once for all time, for all who are willing to believe upon Him alone for salvation (1 Corinthians 15:1-4).
Jesus’ triumphant cry of, “It is finished!” cancels out all false “works-based salvation” doctrines which attempt to add to God’s perfect and completed salvation the efforts of fallen sinful man to the finished redemption that only God could do.
And finally, Jesus’ cry of, “It is finished!” silences the insidious doctrine of Calvinism, which in essence states that God doesn’t love everyone the same – some He loves enough to save them from eternal damnation and others He chooses to send to an eternal Hell. This fatalistic teaching twists the love of God and the choice of Jesus to die in payment for the sins of the world (John 3:16) and the stated fact that He was the propitiation, not only for our sins, but for the sins of the world (1 John 2:2).
I could go on for days writing about how necessary to salvation Jesus’ incarnation is to our salvation, but hopefully this will suffice.
We, in our fallen finite minds, will never this side of eternity grasp all the depth and intricacies of the incarnation of God the Son into humanity. We believe it by faith, but a faith that is rooted and grounded in the “many infallible proofs” (Acts 1:3) that the Bible gives us about how:
God loved the world so much that He gave His only begotten Son (that means the only one of His kind),
that whosoever (that’s inclusive of all as in everyone – anyone)
believeth in him (this excludes all of fallen man’s “filthy rags” efforts to either obtain or maintain God’s free gift of salvation) – believeth – the only thing necessary for acceptance if this gift is to believe according to the scriptures)
shall not perish (in the eternal 2nd death)
but shall have (that is be justified immediately – instantly and eternally saved upon one’s belief)
everlasting life (a promised new and incorruptible body and mind to unite with a believer’s already redeemed spirit) – a redeemed body (Romans 8:22-25; 1 Corinthians 15: 53-55) that is fit to dwell and live forever in the presence of God.
This is the completed purpose of the incarnation of Jesus into the world He created.