There's a reason Christmas is full of joy! Christ became man to save us from sin, show us his love, and restore us as his children.
Christ became a man to heal a rift between God and man that was caused by original sin. The Incarnation, and subsequently Christ's Passion and Resurrection, was the fitting response of a God who loves us, despite our repeated sins and weaknesses. The Incarnation not only gives us hope of redemption – it also allows us to more visibly see God's love and to follow Christ's example in the way by living our lives in imitation of him.
When Adam and Eve committed the first sin, they caused a separation between man and God that they could not repair on their own
One of the first things we learn in Scriptures is that God created men and women in his own image and likeness and that all of his creation was good. In Genesis, we read, “God created man in his image; in the divine image he created him; male and female he created them” (Genesis 1). Along with the gift of life, God the Father also gave men and women the gift of free will – a gift that distinguished them from all other creatures.
St. Athanasius, who teaches quite clearly on the reason for the Incarnation, explains the role that free will played in the Fall: “If they guarded the grace and retained the loveliness of their original innocence, then the life of paradise should be theirs, without sorrow, pain or care, and after it the assurance of immortality in heaven. But if they went astray and became vile, throwing away their birthright of beauty, then they would come under the natural law of death and live no longer in paradise, but, dying outside of it, continue in death and in corruption” (Saint Athanasius, On the Incarnation, no. 3).
When sin first entered into the world through Adam, mankind lost its likeness to God and the grace of original innocence. The Catechism tells us, “Sick, our nature demanded to be healed; fallen, to be raised up; dead, to rise again. We had lost the possession of the good; it was necessary for it to be given back to us” (Catechism, 457). Likeness to God was not something that repentance could gain back for us; man could not save himself from corruption.
Scripture tells us – and of course we know from our own experience in this fallen world – that many sins followed the original one committed by Adam and Eve. The gap between the Creator and man became wider. Athanasius writes, “Had it been a case of a trespass only, and not of a subsequent corruption, repentance would have been well enough; but when once transgression had begun men came under the power of the corruption proper to their nature and were bereft of the grace which belonged to them as creatures in the Image of God. No, repentance could not meet the case. What – or rather – who was it that was needed for such grace and such recall as we required?” (On the Incarnation, 7).
Christ, who is both true God and true man, was the only one who could pay the debt incurred by sin and unite us again to God
Some might ask why God did not simply remove the stain of original sin instantaneously and reunite man with himself. While God the Father could have redeemed us in any way, the Incarnation was the most fitting way. It is clear that because of original sin, it is man that is guilty of the trespass against God that resulted in corruption and death, yet human beings are unable to repay that debt.
Jesus Christ chose out of his own free will (both divine and human) to innocently die on the cross. This choice redeemed the original sin of Adam. As God, Christ was capable of healing the rift between God and man; because Christ was also man, he was physically able to die in our stead.
St. Athanasius tells us, “It was by surrendering to death the body which he had taken, as an offering and sacrifice free from every stain, that he forthwith abolished death for his human brethren by the offering of the equivalent. For naturally, since the Word of God was above all, when he offered his own temple and bodily instrument as a substitute for the life of all, he fulfilled in death all that was required. Naturally also, 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” (On the Incarnation, 9).
Why did God wait become Incarnate? Why not redeem mankind in the beginning of time?
While the Lord's timing will always be somewhat of a mystery to us, it is evident that the Lord is perfect and therefore the timing of his Incarnation must have also been perfect. He could have come to earth at any time, but instead waited until many years had passed since the time of Adam and Eve and after many men and women had chosen to sin.
St. Thomas Aquinas provides sound reasoning for this timing: “Since the work of the Incarnation was directed chiefly to the restoration of the human race through the removal of sin, it is clear that it was not fitting that God become incarnate from the beginning of the human race before sin; medicine is only given to the sick. Therefore, as the Lord himself teaches, It is not the healthy who need a physician, but they who are sick.”
Aquinas continues: “Love does not delay to aid a friend, yet with a care for the right timing and for personal conditions. If a doctor were to give medicine to one who is ill at the very beginning of the sickness, it would be of less value, or even could do more harm than good. So also does the Lord not immediately provide the Incarnation as a remedy, lest it be spurned out of pride, before men recognized their own weakness (St. Thomas Aquinas, Summa Theologica, Third Part, Question 1, Article 5).
We joyfully celebrate the Incarnation at Christmas, recognizing that God's love for us – shown through His birth as a child – gives us the hope of Heaven
Apologist Archbishop Michael Sheehan writes, “It was God's will that every member of our race should become his adopted child destined for the happiness of the beatific vision – a purpose that was frustrated by Adam. But God's mercy and love intervened, and, through the Redemption, restored us to the unspeakably precious gift of sanctifying grace” (Sheehan, 375).
When Christ became man, he did so with the intention of dying for our sins and rising again. His Resurrection ensured that we would be given possibility of joining him in Heaven. Sanctifying grace is restored by Christ's Passion, meaning that we have the possibility of living lives of virtue (directed towards God) because we have his divine assistance.
The Catechism explains this as one of the reasons for the Incarnation: “The Word became flesh to make us ‘partakers of the divine nature’: ‘For this is why the Word became man, and the Son of God became the Son of man: so that man, by entering into communion with the Word and thus receiving divine sonship, might become a son of God.’ ‘For the Son of God became man so that we might become God.’ ‘The only-begotten Son of God, wanting to make us sharers in his divinity, assumed our nature, so that he, made man, might make men gods’ (Catechism, 460).
The Incarnation also shows us concretely that God loves us and gives us Christ as an example for how to live a life of holiness
“The Word became flesh so that thus we might know God's love,” the Catechism teaches. “‘In this the love of God was made manifest among us, that God sent his only Son into the world, so that we might live through him.’ ‘For God so loved the world that he gave his only Son, that whoever believes in him should not perish but have eternal life’” (458).
Christ is also a model of love, which we are called to follow. In the Gospels, he tells us, “I am the way, and the truth, and the life; no one comes to the Father, but by me” (John 14:6). On this, the Catechism instructs, “Jesus is the model for the Beatitudes and the norm of the new law: ‘Love one another as I have loved you’ This love implies an effective offering of oneself, after his example” (459).