Monks, if in any monk or nun, desire or lust, ill-
Suppose a crop of barley had ripened and the watchman were negligent, if a bull were to get into the field, he would indulge himself as much as he liked. However, if the watchman were diligent he would take hold of the bull by the muzzle and give him a sound beating with a stick.
When a monk’s mind is well subdued in this way, it becomes calm, inwardly composed, and well concentrated.
Suppose that a king, or a king’s minister, heard the sound of a lute for the first time, and being captivated by it should order that the sound be brought. On examining the lute, and breaking it into a thousand pieces, burning the splinters, and scattering the ashes, he would wonder how any could be taken in by this thing called a lute.
In the same way, monks, form, feeling, perception, mental formations, and consciousness should be thoroughly examined. S.iv.195.