In another Scriptural passage the progress is a standing still, for it says, You must stand on the rock. This is the most marvelous thing of all: how the same thing is both a standing still and a moving. For he who ascends certainly does not stand still, and he who stands still does not move upwards. But here the ascent takes place by means of the standing. I mean by this that the firmer and more immovable one remains in the Good, the more he progresses in the course of virtue. The man who in his reasonings is uncertain and liable to slip, since he has no firm grounding in the Good but is tossed one way and another and carried along (as the Apostle says) and is doubtful and wavers in his opinions concerning reality, would never attain to the height of virtue.
But if someone, as the Psalmist says, should pull his feet up from the mud of the pit and plant them upon the rock (the rock is Christ who is absolute virtue), then the more steadfast and unmoveable (according to the advice of Paul) he becomes in the Good the faster he completes the course. It is like using the standing still as if it were a wing while the heart flies upward through its stability in the good.
For, since Christ is understood by Paul as the rock, all hope of good things is believed to be in Christ, in whom we have learned all the treasures of good things to be. He who finds any good finds it in Christ who contains all good. He who attained to this and was shadowed by the hand of God, as the text promised (for the hand of God would be the creative power of what exists, the only begotten God, by whom all things were made, who is also “place” for those who run, who is, according to his own words, the “way” of the course, and who is “rock” to those who are well established and “house” to those who are resting), he it is who will hear the One who summons and will see the back of the One who calls, which means he will follow Yahweh your God, as the Law commands.
— Gregory of Nyssa, Life of Moses Book II.