There are moments when the existential questions of life can no longer be answered, ignored, or denied by focusing on our careers, jobs, marriages, families, acquisitions, or accomplishments. We are, to paraphrase the opening of St. Augustine’s Confessions, restless until our hearts rest in God. Who am I? Where am I from? Where am I going? What is my purpose? These are questions of restlessness and wrestling. They are ultimately questions of vocation. They are not answered primarily by what we will do but, rather, by who we will become.

Created in the image and likeness of God (Gen. 1:26-27), each person is called to participate in the life of God and become “partakers of the divine nature” (2 Pet. 1:4).“The human being is an animal who has received the vocation to become God,” St. Basil said. “The human vocation is to fulfill one’s humanity by becoming God through grace” (Olivier Clement, The Roots of Christian Mysticism (Hyde Park, NY: City Press, 1993), 76). We are, the Psalmist declares (Ps. 82:6) and Jesus reminds us (Jn. 10:34), “gods, sons of the most high.”

The incarnation lies at the heart of theosis and the human vocation as Athanasius’ classic statement demonstrates: “He, indeed, assumed humanity that we might become God.” We can become, by grace, what God is by nature. This has become known as the “exchange formula.”   Here are several statements of the exchange formula:

• The Son of God “became what we are in order to make us what he is himself” (Irenaeus, Against Heresies 5).
• “The Word of God became man so that you too may learn from a man how it is even possible for a man to become a god” (Clement of Alexandria, Exhortation to the Greeks 1.8.4).
• “He gave us divinity, we gave him humanity” (Ephrem, Hymns on Faith 5.7.).
• “Let us become as Christ is, since Christ became as we are; let us become Gods for his sake, since he became man for our sake” (Gregory of Nazianzus, Oration 1.5).
• The Word became incarnate “so that by becoming as we are, he might make us as he is” (Gregory of Nyssa, Refutations 13.1).
• “The Son of God became the Son of Man that he might make the sons of men sons of God” (Augustine, Mainz Sermons 13.1).
• “He became like us, that is, a human being, that we might become like him, I mean gods and sons. On the one hand he accepts what belongs to us, taking it to himself as his own, and on the other he gives us in exchange what belongs to him” (Cyril of Alexandria, Commentary on John 12.1.

Theosis encompasses the entire economy of salvation with direct implications for how we live, experience God, and relate to others and the world. Norman Russell writes:

To live theosis, then, means to lead our life in an eschatological perspective within the ecclesial community, striving through prayer, participation in the Eucharist, and the practice of the moral life to attain the divine likeness, being conformed spiritually and corporeally to the body of Christ until we are brought into Christ’s identity and arrive ultimately at union with the Father.

(Norman Russell, Fellow Workers with God, p. 169)

Ultimately, theosis expresses a relationship, a way of being, and a way of living. It is not an escape from the world or the circumstances of our lives but the means by which we engage the world, each other, ourselves, and God. The circumstances of our lives and our spiritual practices are the context for the journey and the raw material we offer God in this mysterious exchange that leads us to holiness and wholeness.