Orthodox Dictionary- Theosis

One of the most obvious differences experienced by those who move into Orthodoxy from western Christianity is the different lexicons used by each tradition. By lexicon I mean, our respective wordbooks or dictionaries. Both East and West not only use different terms to describe our faiths and the way it operates, but even when we use the same terms we often mean something altogether different.  The first term I would like to define from the Orthodox dictionary is “Theosis”.

Theosis: The concept of salvation as deification.

Theosis may be summed up in the phrase, "God became human so that humans might become God." This does not mean that humans can be another god or equal to God, but rather that they can hope to participate in the divine nature.  The notion of deification (Theosis in Greek) is based on the perspective that when Christ was incarnate in the man Jesus, he did take on just one human nature, but all of human nature. He thus made it possible for the reverse to occur – for humans to participate in the divine nature. "The Son of God, as the one through whom the process of creation was fulfilled, came down from heaven into the world and became fully man, i.e. assumed human nature in its integrity and led it to the fulfillment of its God-given destiny, deification." This is the teaching of the New Testament, and the Church Fathers from the beginning until today.

The New Testament:

His divine power has given to us all things that pertain to life and godliness, through the knowledge of Him who called us by glory and virtue, by which have been given to us exceedingly great and precious promises, that through these you may be partakers of the divine nature, having escaped the corruption that is in the world through lust.   
      St Peter the Apostle, 2 Pet 1:3-4

The Church Fathers:

We are not made gods from the beginning; first we are mere humans, then we become gods.    
       St. Irenaeus, Adv Haer III IV:38:4

Let us become the image of the one whole God, bearing nothing earthly in ourselves, so that we may consort with God and become gods, receiving from God our existence as gods   

      St. Maximus the Confessor On Theology, 7.73

For the Son of God became man, that we might become God.

     St. Athanasius, De inc.

He has called men gods that are deified of His Grace, not born of His Substance.  
     St. Augustine of Hippo

The Word became flesh 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.  
     St. Irenaeus, Adv Haer III

Let us applaud and give thanks that we have become not only Christians but Christ himself. Do you understand, my brothers, the grace that God our head has given us? Be filled with wonder and joy--we have become veritable Christs!   
      St. Augustine of Hippo

The highest of all things desired is to become God.     
      St Basil the Great

Contemporary Fathers:

“Salvation,” is considered a product of that decisive moment which occurred in the in the course of human history though the entrance of the divine into its path. God brings his life to man and man participates in this life, when he lives freely, consciously and existentially, in an unceasing process towards perfection, through strengthening his will and developing his spiritual powers. What happened with the human nature assumed by Christ, is repeated in every man. This is effected by the energy of God and the effort of man in cooperation. This is salvation; completion of personality, transfiguration, elevation to the throne of God, theosis. 
       Panayiotis Christou

Salvation as theosis is understood to be the experience of human participation in God life and power which precisely what is meant by salvation. This is the first word in the “Orthodox Dictionary”.