the purpose of our life is blessedness or, what is the same thing, the kingdom of heaven or of God... not only to behold the Trinity, supreme in Kingship, but also to receive an influx of the divine and, as it were, to suffer deification; for by this influx what is lacking and imperfect in us is supplied and perfected. And the provision by such divine influx of what is needed is the food of spiritual beings.
This passage delivers the most technically precise definition in the corpus: divine influx is the mechanism of deification itself, supplying what is imperfect in the creature and constituting the very nourishment of spiritual existence.
, The Philokalia, Volume 2, 1981thesis