A thief wanted to steal a very valuable and large bell, so he decided to smash it so that he could carry it home. But when he hit it, the loud clang surprised him and he covered his ears, thereby muffling the sound.

He decided to use cloth to plug his ears, foolishly thinking it quieted the bell so that he could hit it repeatedly. Neighbors soon heard the sound and caught the thief in the act.

Thus, the moral of the story is that the sound of the bell exists objectively; it won’t be silenced even if you cover your own ears. This story gave rise to the idiom "掩耳盗铃" (covering ears to steal a bell) and vividly explains the basic principle of dialectical materialism: all things exist objectively—a fact that should not be ignored, or else you will deceive yourself and suffer the consequences.