How did our salvation begin?
Our Salvation begins with the Incarnation of our Lord, Jesus Christ.
God the Father sent His Son into the world to bring the world back into union with Himself. Paul says, God was in Christ reconciling the world unto Himself. (2Corinthians 5:18) Saint John the Theologian writes, For God so loved the world that He gave His only begotten Son, that whoever believes in Him should not perish but have everlasting life. (John 3:16) We know that the Son of God has come and has given us an understanding, that we may know Him who is true; and we are in Him who is true, in His Son Jesus Christ. This is the true God and eternal life. (1 John 5:20)
Luke records for us the story of the Son of God’s conception and birth. His birth was a miracle brought about by the Holy Spirit through the virgin Mary. It was from Mary that Jesus took on his humanity. He became like us in all ways. Yet, He remained totally God. Paul writes, For in Him dwells all the fullness of the Godhead bodily (Col 2:9). Conceived by the Holy Spirit and given human form though the Virgin Mary, He became like us, uniting humanity and divinity.
These two natures are important because He can reveal to us God in a way different than any prophet. Through His presence on earth we can gain mystical knowledge about the Holy Trinity and learn how we, in our humanity, can become like Him and live in communion with God. Christ united human nature with divine nature showing us how all of us can share in the life and glory of God. His sinless way of life opens the way for us to live life as God intended for us.
Saint Basil put it very clearly when he wrote,
Thou didst not turn Thyself away forever from Thy creature, whom Thou has made, O good One, nor didst thou forget the work of Thy hands. Through the tender compassion of Thy mercy, Thou didst visit him in various ways; Thou didst send prophets; Thou didst perform mighty works by Thy Saints, who in every generation were well-pleasing unto Thee; Thou didst speak to us by the mouths of thy servants the prophets, foretelling us of he salvation which was to come; Thou didst appoint angels as guardians. And when the fulness of time had come, Thou didst speak to us through Thy Son, Himself, by Whom Thou didst also make the ages; Who, being the radiance of Thy glory and the image of Thy person, upholding all things by the Word of His power, thought it not robbery to be equal to Thee, the God and Father. He was God before the ages, yet He appeared on earth and lived among men, becoming incarnate of a holy Virgin. He emptied Himself, taking the form of a servant, being likened to the body of our lowliness, that He might liken us to the image of His glory.
The union and the two natures of Christ were affirmed in three Ecumenical Councils. (3, 4 and 6)