God became human so that people might become gods
Athanasius


We non-fundamentalist western Christians tend not to think too much about what happens when we die. Hell is no longer a serious possibility for most of us who are even halfway liberal mainline Protestants, Anglicans, or Roman Catholics. We do not deign to believe in a God who would be so judgemental as to consign people to the eternal slammer. On the other hand, how excited can we get over spending eternity floating on a cloud dressed in an angel costume? Some fans of process theology think that when we die we exist only as memories in God's (admittedly huge) data banks.
So what sense do we make of the above quote by Athanasius, the fourth-century bishop of Alexandria? Isn't that a bit too outrageous, even if we're grasping for a few optimistic straws? Becoming a god? Isn't that what the Mormons promise themselves after a lifetime of taking part in temple ordinances and putting on holy underwear?
Strange as it sounds, this doctrine has been at the heart of Eastern Christian theology and spiritual practice for nearly its entire history. But let's clarify what theosis means.
Right off the bat, theosis is not the same as pantheism. The essence of our human nature is not replaced by divine nature. As Bishop Kallistos Ware, perhaps the leading English-language Orthodox theologian, puts it,
we are able to affirm a direct or mystical union between man [sic] and God...
but at the same time we exclude any pantheistic identification between the
two: for man participates in the energies of God, not the essence. There is
union, but not fusion or confusion. Although "oned" with the divine, man still
remains man; he is not swallowed up or annihilated, but bewtween him and
God there continues always to exist an"I-Thou" relationship of person to
person.
(The Orthodox Way, p. 23)
The doctrine of theosis--also known as deification, divinization, or partaking of the divine nature--is scripturally rooted mainly in Psalm 82:6 (Now I say to you, "You are gods, and all of you children of the Most High) and in 2 Peter 1:4 ( about being "partakers of divine nature.)
In the eastern tradition, we achieve theosis by prayer, meditation, moral living, and, most particularly, participation in the sacraments, especially the Eucharist.