"Great is the mystery of godliness [piety]: God was manifest in the flesh" (I Tim. 3:16). These words of the holy Apostle testify that the miracle of the incarnation of the Son of God exceeds the understanding of our limited mind. Indeed, we can believe, but cannot explain, the event that took place two thousand years ago in Bethlehem: that, in the one Person of Jesus Christ, two natures so different and contrary in essence were joined together: the superterrestrial, eternal and infinite divine nature with the material, limited and feeble human nature.
Nonetheless, the Gospels and the apostolic epistles reveal to us, to the extent of our abilities, certain aspects of the miracle of the incarnation of the Son of God. Saint John the Theologian, at the very beginning of his Gospel, elevates our thought to the pre-eternal existence of the Second Person of the Most Holy Trinity, Whom he calls the Word, saying: In the beginning was the Word, and the Word was with God, and the Word was God. The same was in the beginning with God. All things were made by him; and without him was not anything made that was made. And the Word was made flesh, and dwelt among us (John 1:1-3, 14).
The Son of God's name, the Word, indicates that one must not understand His birth from the Father in the sense of an ordinary birth: it occurred passionlessly and without separation. The Son of God is born from the Father like a word is born from a thought. A thought and a word are distinct from one another, and at the same time inseparable. There is no word without a thought, and a thought is without fail expressed in a word.
The subsequent apostolic preaching reveals all the more fully the truth of Christ's divine-human nature: He is the only begotten (the only) Son of God, Who was begotten of the Father before all ages, i.e., He is eternal, as God the Father is also eternal. The Son of God has the same divine nature that God the Father has, and is therefore omnipotent, omniscient and omnipresent. He is the Creator of the visible and invisible worlds, and of us men. In a word, He, being the Second Person of the Most Holy Trinity, true and perfect God. Faith in Jesus Christ as the incarnate Son of God represents the stronghold or rock upon which the Church is established, according to the word of the Lord: Upon this rock I will build my church; and the gates of hell shall not prevail against it (Matt. 16:18).
Being perfect God, Christ the Saviour is at the same time also perfect Man. He had a human body and soul with all its properties - reason, will and senses. As a man, He was born of the Virgin Mary. As the Son of Mary, He obeyed her and Joseph. As a man, He was baptized in the Jordan and went around the towns and villages with His salvific preaching. As a man, He experienced hunger, thirst, fatigue; he had a need for sleep and rest; he endured painful sensations and physical sufferings. Living the physical life inherent to a man, the Lord also lived a spiritual life as a man. He strengthened His spiritual powers by fasting and by prayer. He experienced human feelings - joy, wrath, sorrow; he shed tears. In this way, the Lord Jesus Christ, having taken on our human nature, was in all things like unto us, except for sin.
Having two natures, Jesus Christ also had two free wills. Jesus Christ's rational, conscious, human will invariably subordinates its human aspirations and desires to His divine will. But the human will in Christ is clearly visible during His difficult experiences in the garden of Gethsemane: O my Father, if it be possible, let this cup pass from me: nevertheless not as I will, but as thou wilt (Matt. 26:39).
Thus, by His obedience to God the Father, the Lord Jesus Christ corrected our disobedience and taught us to put God's will above our own desires.