If you’ve never read St. Athanasius’ book On the Incarnation, I highly recommend you do so. It is a very helpful work for understanding why Christ had to take on human flesh, die and rise again for our salvation.
In the beginning of his book, Athanasius makes a very interesting point about Christ being our life. What does he mean—for Christ to be our “life?” Athanasius answers that by first contemplating on the creation and fall of mankind. He writes, “The presence and love of the Word had called them [Adam and Eve] into being; inevitably, therefore when they lost the knowledge of God, they lost existence with it; for it is God alone Who exists, evil is non-being, the negation and antithesis of good” (30).
What he means is this: humanity, though created mortal, was truly immortal as long as united to the Word. The Word sustained Adam and Eve and was their source of life.
Then the LORD God formed the man of dust from the ground and breathed into his nostrils the breath of life, and the man became a living creature.Genesis 2:7, ESV
The New Testament makes it strikingly clear that true life comes only from the Word, that is—the Son of God.
In the beginning was the Word, and the Word was with God, and the Word was God. He was in the beginning with God. All things were made through him, and without him was not anything made that was made. In him was life, and the life was the light of men.John 1:1-4, ESV
That text is very fascinating. Jesus was there at creation, and in him was life.
For by him all things were created, in heaven and on earth, visible and invisible, whether thrones or dominions or rulers or authorities—all things were created through him and for him. And he is before all things, and in him all things hold together.Colossians 1:16-17, ESV
Jesus is the source of all things that were created, including—especially—humanity.
The life was made manifest …1 John 1:2, ESV
According to Athanasius, in the beginning, it was the Word of God—Christ—that was breathed into the nostrils of Adam. Only by union with the Word did humanity exist truly.
We know what happens in Genesis 3, however. Adam and Eve disobey God’s command to not eat from the tree of the knowledge of good and evil. And what did God say would happen to Adam and Eve if they disobeyed? They would surely die.
Did Adam and Eve keel over right after eating from the tree? No—they went right on living their lives. Well, what did God mean when He said, “in the day that you eat of it you shall surely die,” (Gen. 2:17, ESV)?
Many will answer that question this way: God had a twofold meaning. First, every human would die eventually because death now entered the world. Second, the very moment Adam and Eve sinned, they died spiritually. I agree with this idea, but what does it mean for someone to die spiritually? And is there any connection between that and dying physically?
Athanasius further explains, “God had not only made them out of nothing, but had also graciously bestowed on them His own life by the grace of the Word. Then, turning from eternal things to things corruptible, by counsel of the devil, they had become the cause of their own corruption and death” (30).
For humanity to die spiritually means that their union to the Word, to Life itself, is severed. And because people are no longer united to Life, they are in a constant state of corrosion until the day of their death. This is everyone’s dilemma. Though we live, yet are we dead. Though we exist, we exist as vapors and phantoms on the way to our home—the grave. And this is because of sin.
And you were dead in the trespasses and sins in which you once walked …Ephesians 2:1-2, ESV
Humans are dead because they are sinners. Sin has separated us from the breath of life. We walk in the way of death. What is the solution, then?
But God, being rich in mercy, because of the great love with which he loved us, even when we were dead in our trespasses, made us alive together with Christ …Ephesians 2:4-5, ESV
God must breathe life into us once again. We must be united to the Word. And the Word became flesh (John 1:14) in order for this to happen.
Jesus said to them, “I am the bread of life; whoever comes to me shall not hunger.”John 6:35, ESV
Jesus said to him, ‘I am the way, and the truth, and the life. No one comes to the Father except through me.”John 14:6, ESV
The life was made manifest, and we have seen it, and testify to it and proclaim to you the eternal life, which was with the Father and was made manifest to us … and indeed our fellowship is with the Father and with his Son Jesus Christ.1 John 1:2-3, ESV
Here is how Athanasius saw the relationship between the incarnation and humanity’s salvation from eternal death (35):
… Through this union of the immortal Son of God with our human nature, all men were clothed with incorruption in the promise of the resurrection. For the solidarity of mankind is such that, by virtue of the Word’s indwelling in a single human body, the corruption which goes with death has lost its power over all.
This is why there is no salvation apart from Christ (Acts 4:11-12), and why we must believe in Christ and share Christ. For only through believing in Him do we have life in His name (John 20:31) and will we be brought back into the state God intended for us. We must always continue to hold to the truth that Jesus is the only way to everlasting life, because He is Himself that life. Only those united to Christ are alive and will be alive forevermore.