In the Life of Moses, Gregory writes in response to the question: What is the perfect life?
Even though he will explore the question by using Moses as a template for the pursuit of a virtuous life, he actually starts his treatise with a reflection on Philippians 3:13-14 because “that divine Apostle, great and lofty in understanding, ever running the course of virtue, never ceased straining toward those things that are still to come.” (I, 5)
For Gregory, perfection comes in the process, which is quite different from the neoplatonism of his day, that understood perfection as fixed and unchanging. And because the process is what is important, Gregory argues that the pursuit of virtue can never cease in this lifetime. It is an infinite process without end in this life. For each time a new level of virtue is reached, the Christian looks on the horizon and sees that she hasn’t reached the end, but that there is indeed more to pursue.
Not only that, if a Christian stops pursuing virtue it does not mean that she has merely stopped, but, in fact, she has traded one race for another:
“Just as the end of life is the beginning of death, so also stopping in the race of virtue marks the beginning of the race of evil.” (I, 6)
This is because God is himself absolute virtue (I, 7), and so the pursuit of virtue is participation in God. To abandon this pursuit is to abandon God.