our mutability is the possibility of growth

But in truth the finest aspect of our mutability is the possibility of growth in good; and this capacity for improvement transforms the soul, as it changes, more and more into the divine. And so what appears so terrifying (I mean the mutability of our nature) can really be as a pinion in our flight towards higher things, and indeed it would be a hardship if we were not susceptible of the sort of change which is towards the better. One ought not then to be distressed when one considers this tendency in our nature; rather let us change in such a way that we may constantly evolve towards what is better, being “transformed from glory to glory” (2 Cor 3:18), and thus always improving and ever becoming more perfect by daily growth, and never arriving at any limit of perfection. For that perfection consists in our never stopping in our growth in good, never circumscribing our perfection by any limitation.

- St Gregory of Nyssa, On Perfection