Man failed God and failed himself through his revolt against God. However, God did not abandon him. God kept following man with His loving care and providence. God prepared man's salvation in the same eternal Logos of God, through whom we are created, so that even after our fall we may return to immortality (St. Athanasios).

The plan of God for man's salvation is called the plan of "divine economy," i.e. divine dispensation. God the Father conceives the plan, the Son executes it, the Holy Spirit fulfills it and leads it to perfection and finalization.

God the Father acts out of love for man, in sending His own Son for the salvation of the world (John 3:16). When the time was ripe, after a series of purifications throughout the Old Testament that led to the Virgin Mary who could respond to God, accepting man's salvation on behalf of humankind, God sent forth His only-begotten Son, "born of woman, born under the law, to redeem those who were under the law, so that we might receive adoption to sonship" (Gal. 4: 4-5).

a) Christ's Incarnation and the Mystery of Salvation

Christ saved humankind through what He is, and through what He did for us. Beginning with St. Irenaeos, the Greek Fathers continually reiterate the statement that the Incarnate Son of God "became what we are (a human being) so that we may be deified," says St. Athanasios. By assuming our human nature, the Incarnate Logos, a divine person, brought this humanity to the heights of God. Everything that Christ did throughout His earthly life was based on the presupposition that humanity was already saved and deified, from the very moment of His conception in the womb of Mary, through the operation of the Holy Spirit.

b) Jesus the Christ, the God-Man

Anointed by the Holy Spirit of God since its conception, Christ's humanity is the humanity of the Messiah (the Anointed one) since the beginning of its existence.

Christ is at the same time the son of the Virgin, but also the natural Son of God, by His very nature. His humanity is a real humanity, with a body and soul, which suffered hunger and thirst, which suffered humiliation and the Cross. The Church condemned such heresies as that of the Docetists, who said that Christ's humanity was not real, Arios who taught that there was no soul in Jesus, and Apollinarios of Laodicea who taught that there was no reason in Jesus.

The Church also defended the divinity of Jesus against the Ebionites, who denied Christ's divinity, the Monarchian heresy which subordinated the Son to the Father, and Arianism, which also denied the divinity of the Logos of God. Against all these heretics the Church upheld the doctrine that Christ, a divine person, is "true God of true God," for He is the only begotten Son of God, not in a metaphorical, but a natural sense. He has the divine properties of omniscience and preexistence in terms of God's creation. He is the only one without sin: He operates miracles through His divinity, accepts divine honor and worship due to the divinity, and accepts faith in Him.

Humanity and divinity are hypostatically united together: the two natures exist in the one person of the Word who became flesh, a divine person (or hypostasis). Christ exists "in two natures," without being of two natures; the two natures exist united together "without confusion, without change, without division, without separation." (Council of Chalcedon). The first two adverbs are addressed against the heresy of Eutyches and the monophysites who confused the natures and the last two against the Nestorians, who separated and divided humanity and divinity in Christ.

Consequently, Christ has two wills also and two operations, one human and one divine; the two work together "to achieve man's salvation"; however, the human will and operation is always subjected to the divine (Third Council of Constantinople, the Sixth Ecumenical, against Monothelitism).

The consequences of this hypostatic union of the two natures in Christ are the "coinherence" of human and divine nature, the communicatio idiomatum, the natural sonship of Christ's humanity, one worship of the two natures in Christ, deification of Christ's human nature, Christ's double knowledge and power (however, attributed to one person), Christ's absolute unsinfulness, and the Mother of God being truly Theotokos and Virgin before, during, and after she gave birth to the only-begotten Son of God.

c) Jesus the Prophet, the Priest, and the King

Jesus had the following obstacles to overcome in order for Him to accomplish the work for which He came (theosis): the obstacle of nature, the obstacle of sin, the obstacle of death, and the dominion of the devil. The obstacle of nature was overcome with His Incarnation; the obstacle of sin and death was overcome by the Cross and the Resurrection of Jesus. The dominion of the devil was overcome by Christ's descent into Hades (Hell).
According to Eusebius of Caesaria and the patristic tradition of the Church, the mission of Christ (continued by the Church) is threefold: Prophet, Priest, and King.

As a Prophet, Jesus taught humankind the truth of God, being Himself the Incarnate Truth, the Way and Life. Christ's teaching is characterized by clarity and lucidity, simplicity and completeness. Christ is the teacher who backs His teaching with His life.

As a Priest, Christ offers Himself as a victim "for the life of the world." Through His sacrifice on the Cross, Christ "redeems us from the curse of the law, by His precious blood," bestowing "immortality upon humankind" (Troparion of the Crucifixion). The blood shed upon the cross washes away our sin; as it fell upon Adam (man's) skull and dry bones (according to a pious tradition Adam's tomb lay under the place of crucifixion on Golgotha) they were made alive again; man's poisonous blood was replaced with the life-giving blood of God (Troparion of the Feast of the Exaltation of the Cross). Through Christ's death upon the Cross, man was restored to life.

Christ is King throughout His earthly life, for He came to establish and to announce the Kingdom of God (see Matt. 4:17). However, the highlights of His Royal Ministry are the Cross itself (for, according to St. John Chrysostom, Christ dies as the King who offers His life for His subjects); the descent into Hades to announce salvation to "those who were asleep there from all ages" (Troparion of Holy Friday); the Resurrection, through which Christ "tramples down death by death, bestowing everlasting life to the dead"  (Resurrection hymn); Christ's Ascension into heaven, through which He reenters into the Father's glory; and Christ's glorious coming again.

d) The Mission of the Holy Spirit

The last part of the plan of salvation (divine economy) is fulfilled by the Holy Spirit of God (economy of the Holy Spirit).

The Spirit of God prepares for the coming of Christ in the Old Testament period, becomes the ointment of Christ's flesh the day of the Annunciation, accompanies Christ throughout His mission on earth, and applies Christ's work, both saving and deifying, to each Christian individually, through the sacramental life of the Church. Christ has achieved our salvation and deification in an objective way, in our nature. The Spirit applies salvation and deification in a subjective way, to our persons. Divine grace, the Church, and the sacraments are the working of the Holy Spirit.

e) Divine Grace

By divine grace we understand the saving and deifying energy of God, made available through Christ's work, and distributed by the Holy Spirit, the source of grace and sanctification.

Divine grace, the work of the Holy Spirit, is a free gift, necessary for our salvation, non-coercive, which requires our cooperation (synergy). Our response to the grace of God is our works of love, which are the fruits of God's grace working in us. We are justified by God's grace. However, this justification is not real, unless it produces the "works of righteousness."

f) The Church of Christ

The place where the saving and deifying grace of the Holy Spirit is at work is the Church of Christ. The Church is at the same time the image of the Holy Trinity, the people of God, the Body of Christ, and the Temple of the Holy Spirit. All these aspects are necessary for a complete image of the Church.

The Church is the great sacrament of salvation that Christ has instituted in the world. It is the Ark of salvation, and the inaugurated Kingdom of God. Its unity is not affected by schism and heresy; its holiness is not affected by sin; its catholicity and truth is not affected by partiality and falsehood. Founded upon the Apostles, she continues the apostolic mission and ministry in the world, being the "pillar of truth," never failing in accomplishing her mission.

g) The Communion of Saints

The Church thus conceived is not just another human organization; it is a gathering of people who profoundly share the life of faith, the new life in Christ, the life in the Holy Spirit, the life of God. The Church can best be characterized as a "communion of saints." For all its members are called to holiness, through their rite of incorporation into the Holy Body of Christ, the Temple of the Holy Spirit, the People of God. Militant on earth and triumphant in heaven, the Church is only one family, sharing in the same means of grace, the holy sacraments.