Barnes again: “For Gregory the transcendence of God includes the capacity to produce; indeed, Gregory’s conception of this capacity as a dunamis means not only that this capacity exists as a natural capacity in God, but because this capacity is the dunamis of the divine nature, GOd’s kind of existence is the kind that (re)produces.”
Then this provocative kicker: “The distinction among Persons means that the inherent productivity of the divine nature has two different expressions or appropriations. The first Person is productive (thas is, is God) by generating the Second; the second Person is productive (that is, is God) by creating.”