Temperance as a riverbank for virtue

"Discipline, moderation, chastity, do not in themselves constitute the perfection of man.  By preserving and defending order in man himself, temperantia creates the indispensable prerequisite for both the realization of actual god and the actual movement of man toward his goal.  Without it, the stream of the innermost human will-to-be would overflow destructively beyond all bounds; it would lose its direction and never reach the sea of perfection.  Yet temperantia is not the stream.  But it is the shore, the banks, from whose solidity the stream receives the gift of straight unhindered course, of force, descent, and velocity."

- Josef Pieper, Four Cardinal Virtues, 175