It is fitting that we exchange gifts at Christmas, because our life in Christ is a gift exchange. He came among us precisely to exchange gifts. Jesus is God the Son, the Second Person of the Trinity, who joined his divinity to a human nature. In joining a human nature, he joined divinity to humanity. Vatican II pointed out that in joining a human nature, God the Son is intimately present to every man (joined himself to every man, as it were). But he does not force himself upon anyone. His Incarnation is an offer of exchange, and the exchange is: If you give me your humanity, I will give you my divinity.
Jesus is both human and divine, and he offers us the opportunity to become both human and divine; for it was St. Athanasius who said: "God became man so that man might become god".
Parents who have their children baptized carry out this exchange; parents offer their children on their behalf. They give to Christ the humanity of their child, and in return, Christ gives that child his divinity. The result is that the child leaves the Church a different creature than when he or she arrived. That child has been deified, divinized, filled with divine grace (theosis). That child is human, but at the same time more than human. That child shares in the divine nature, and so he or she is more than human without ceasing to be human, and as a result that child has capacities that he or she would not have without divine grace, such as the power to believe what Christ has revealed about himself (faith), the capacity to hope for eternal life, and the power to love God intimately, as an intimate friend between whom secrets are shared. None of this is possible without divine grace. And of course, the child receives the 7 personal gifts of the Holy Spirit, as seeds that will unfold as the child continues to grow in faith. And there's no doubt in my mind that parents for the most part have no idea the good they are doing for their children and for the world in offering their children for baptism. They have a sense that this is a good thing, because they arrange for baptism, even when they are not fully practicing the faith themselves. But they don't fully realize how much good they are doing for their children and for the world in doing so.
That is the exchange that Christ offers us. I will give you my divinity if you give me your humanity, and it is a giving that we have to renew for the rest of our lives, because we tend to drift away from him over the course of the years. We tend to get caught up in things that ultimately don't matter; we get distracted by fear and the lures of pleasure, power, and money, and sin blinds the mind to a certain degree, which allows us to veer away even further. And if we are reflective enough, we become aware of an increasing emptiness--these things don't fulfill us, and the reason is that we became a "son of God", deified, divinized, sharers in the divine nature. That's our deepest identity. In 1920, army chaplain and poet G. Studdert Kennedy wrote:
If I am the son of God, nothing but God will satisfy my soul; no amount of comfort, no amount of ease, no amount of pleasure, will give me peace or rest. If I had the full cup of all the world's joys held up to me, and could drain it to the dregs, I should still remain thirsty if I had not God. If the feast of all the good things of life, pleasures and powers that have been and that are, could be laid out before me and I could eat it all at one meal, I should still be hungry if I had not God. Nor would it satisfy my soul, if I could be assured of an infinite extension of this present life at its best, apart from God. If the feast of this life's goods could last forever, yet would I start up from the table satiated but still unsatisfied, because I had not God. There is not enough in ten material worlds to satisfy a fully-developed human soul - I must have communion with God. Whatever tends to break that communion is an enemy of mine, however much it may pretend to be a friend. However stubbornly I may stick to the delusion that I can live without Him, however closely I may cling to the idol that I put up in His place, sooner or later, in this world or in the next, the idols and delusions will have to go.
There is another side to this exchange. In joining his divinity to our humanity, Christ joined the divine joy to the suffering of our humanity, and this is something we can experience as well. If I am a son of God, if Christ's divinity is joined to my own humanity as a result of my own willing acceptance of that divinity, and if I have made some progress in the spiritual life, then I can sense the joy of that divinity in the midst of suffering, especially physical suffering. Although the suffering is horrible, whether it is a kidney stone, a painful illness, or the pain of dying of old age, at the very core of one's being, there is joy. Not exhilaration, not exuberance, but a tiny and subtle flame of joy suffering cannot touch or extinguish, only illuminate. In my experience with dying patients, it is always those with real faith who, although they are experiencing some agony, have not lost charity, but are still full of gratitude, still thoughtful, still good natured. This is rarely the case with people who are dying. There is a clear difference between dying patients who have lived a life of faith, hope, and charity throughout their lives, and those who seemed to have refused the divine exchange.
And so there is really nothing to fear when it comes to pain and suffering, if we have given our humanity to him. At the deepest center of our nature, we will detect the divine light, which illuminates and brings a degree of warmth in the midst of that suffering, so that the suffering does not overwhelm us with fear and despair.