A quote
We should therefore proceed to the task of freeing ourselves from faults with all the more courage because, when once committed to us, the good is an everlasting possession; virtue is not unlearned. For opposites find difficulty in clinging where they do not belong, therefore they can be driven out and hustled away; but qualities that come to a place which is rightfully theirs abide faithfully. Virtue is according to nature; vice is opposed to it and hostile.
Seneca·Letter 50 — On Our Blindness and Its Cure (§8)·trans. Gummere