What is Orthodox Meaning of Theosis or Union with God

Saint Theophan the Recluse says, that the aim of an Orthodox Christian is "a living unity with God." This referred to as "theosis." What is this union or unity? This does not mean an identity with God where we lose our human identity and become one in essence with God. Many Protestants reject this Orthodox understanding because they fail to appreciate that one can have a union with God without becoming identified with God. Fr Staniloae tells us, "Christian teaching adopts a middle position between mysticism of identity and the irreducible separation between man and God." Both extremes are rejected by Orthodox Christians. To understand theosis we must have a clear view of the nature of God.

God is a reality of unlimited power that is not surpassed or limited by any creature or thing. All of creation, the whole of the world, is the result of God's creation, His free will. All was created from nothing. God is beyond all creation. The world is not made up of God particles. There is nothing of God's being in the constitution of the world.There is no possibility for identity with God of any of His creation. The reality of creation is that it cannot become uncreated by any form of progression. But there is more.

Fr. Staniloae says,

On the other hand, the Word God used to create the world, as a manifestation of His will was in some way an expression of power. God did not mix His power with the nature of the world. Nevertheless, without the descent of His power into the nothingness from which He took it, it couldn't have been produced; and without the presence of His power around it and even in the immediate intimacy of everything in it, the world would not be able to sustain itself and develop. Without the power of God in the final analysis, the world would be reduced to the nothingness which has no power to sustain it... Thus everything in the world has intimately within it, the immediate presence of a working power of God.

We can never become part of the essence of God but we only exist in His power. It is by His power working in us, His presence, that we find ourselves in union with God. It is only because of this union that we exist.

Saint Theophan says, "It may seem strange that communion with God must be attained when it is already present."  While we exist in communion with His power we are not aware of this reality. We see ourselves as independent beings like we are of our own making. We act as if we are the creator of our life.

The union with God that Orthodox understand as our aim is about an understanding that we live in Him. Fr Staniloae says, 

"Christian spirituality teaches that attainment of union is possible only by gradual growth and an understanding of it by the consciousness... It requires the cleansing of the soul and mind from worldly preoccupation." 

It is only with a clean consciousness that we can attain an understanding of this union which is neither an identity with God nor a absolute separation. Union is a matter attaining a consciousness of His presence and the reality that our existence depends on His power. It is an ongoing process until it become a living unity. Saint Theophan describes it as a "movement from mental communion with God to actual live, perceptible and manifest communion."

Our consciousness has inherent in it a deep seated knowledge of an infinite reality that supports our existence. It is this inherent knowledge that gives us the motivation to know and to seek this union with God. Our "mind is made to seek God." We have an intimate feeling of an infinite reality that we strive to know. This desire indicates the kind of direct relationship that is possible with God. There is inherent in this inner feeling a value of love and we sense a connection like a "delicate tread".  This power that sustains us nurtures our seeking and understanding that comes and goes from our consciousness, showing us ever more the reality of a direct relationship that we are destined to attain.

Often Protestants maintain an intellectual stance insisting on an absolute separation of man and God. They claim it is only in the Word as found in Scripture that we know God. The Word of Jesus is only understood intellectually. For in their view the Word is totally separate from us. They miss this mystical reality of His grace that sustains all creation.

Fr. Staniloae writes:

God extends Himself by His power, to the point where prophetic organs proclaim His revelational word. But for the listener to gain certainty of the divine character of this word, the divine power must take one more step, namely into his soul, as radiation from the word itself. "

More is possible than knowledge of God from a distance, such as by reading Scripture. There is a feeling that takes place within our soul which is more than a distant intellectual kind of knowledge.

Since we can never achieve an identity with God, our knowledge is fully developed based on a personal relationship that leads us to a face to face vision. It is like knowing your neighbor. You can't know all about Him based on your own effort. He must reveal himself to you based on his own initiative. This is also true for God. A "vision of God cannot be reached without a special grace from Him."

This vision of unity or union comes after much effort to purify our consciousness. We gain glimpses and then He seems to disappear. Saint Marcarius the Great writes. The spiritual influence of God's grace within the soul works with great patience, wisdom and mysterious management of the mind, while the man for long times and seasons contends in much endurance; and then the work of grace is proved to be perfect in him."

Saint Theophan writes,

Finally, when this period of hidden communion in the soul is over...God dwells in man in a special manner. He visibly fills him, unites Himself to him and communes with him. This is the goal man strives to achieve through all his ascetic struggles and labors...

Fr. Staniloae writes that the spiritual Christian says,

"I am man, but I live as God, by what God has given me; I am man, but I am on God's level by the grace with which He has been pleased to cloth me..." This reflects the expression of the Apostle Paul: "I live; yet not I, but Christ lives in me" (Gal 2:20). In other words, my personality hasn't ceased to exist because I am conscious of it at the same time as I affirm it; my personality now lives the life of Christ. I am still a man by nature, but I have become Christ by the powers by which I myself now live. This is the experience of the Christian on the highest peaks of spiritual life.

Saint Diadochos of Photiki says, 

"Grace illumines his whole being with a deeper awareness, warming him with great love of God."

Reference: Orthodox Spirituality, pp30-39 by Fr. Dumitru Staniloae