John Cassian, Conferences I–X IV.16: Of the excitements of the flesh, without the humiliation of which we should fall more grievously

Of the excitements of the flesh, without the humiliation of which we should fall more grievously.

To the fact then that the pride which results from this purity would be more dangerous than all sins and wickednesses, and that we should on that account gain no reward for any height of perfect chastity, we may call as witnesses those powers of which we spoke before, which since it is believed that they experience no such fleshly lusts, were cast down from their high and heavenly estate in everlasting destruction simply from pride of heart. And so we should be altogether hopelessly lukewarm, since we should have no warning of carelessness on our part implanted either in our body or in our mind, nor should we ever strive to reach the glow of perfection, or even keep to strict frugality and abstinence, were it not that this excitement of the flesh springs up and humbles us and baffles us and makes us keen and anxious about purifying ourselves from spiritual sins.