Chapter 10.
How no one can obtain perfect virtue and the promised bliss by his own strength alone.
For the will and course of no one, however eager and anxious, is sufficiently ready for him, while still enclosed in the flesh which wars against the spirit, to reach so great a prize of perfection, and the palm of uprightness and purity, unless he is protected by the divine compassion, so that he is privileged to attain to that which he greatly desires and to which he runs. For “every good gift and every perfect gift is from above, and comes down from the Father of lights.” “For what do you have which you did not receive? But if you have received it, why do you glory as if you had not received it?”
Source: Institutes (New Advent)