It is amazing how quick theosis brings changes of heresy onto someone. I think it stems from all the popular anti-Mormon literature, since it is what I am accused of being (Mormon).

Thanks. I often bring up theosis in my writings, but thought someone might like to know what it actually is about.

There are indeed sources before St Athanasius who brings up theosis — I started with St Athanasius because his wording of it was the most famous (and the one I like to use the most). But St Irenaeus is an important pre-Nicene representative of this tradition, and he of course bring in the sacramental side (eucharist — medicine of immortality) to the question.

I’ve mostly avoided the whole “image and likeness of God” aspect (except giving a few nods to it here and there) of theosis because it brings in more questions and debates which serve as the foundation for many divergent theological opinions. There is even disagreement as to what it means to talk about an “image” and a “likeness.” I have my take with it, of course.

I do make a brief footnote to the fact that in the modern era, more investigation goes on here, and point to sources who do so; but because I wanted to keep this a simple presentation (as simple as possible) I thought the whole question could be done another time (in a post about the same size as what I wrote here when parts 1 and 2 are combined).

I hope by the time these two posts are done, people at least will understand what theosis is and not confuse it for what it is not.