Otherwise; What is denoted by the sea, but the world, and what by the mill-stone, but earthly action? which, when it binds the neck in the yoke of vain desires, sends it to a dull round of toil. There are some who leave earthly action, and bend themselves to aims of contemplation beyond the reach of intellect, laying aside humility, and so not only throw themselves into error, but also cast many weak ones out of the bosom of truth.
Whoso then offends one of the least of mine, it were better for him that a mill-stone be tied about his neck, and he be cast into the sea, that is, it were better for a perverted heart to be entirely occupied with worldly business, than to be at leisure for contemplative studies to the hurt of many.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).
Also cites: Mor., vi, 37