The General and The Monk

I'm not sure of the origin or accuracy, but I have always loved this tale:

In ancient times there was a conquering army going through villages wreaking havoc and mayhem. The soldiers killed indiscriminately and were especially harsh on the monks, taking special care to humiliate and torture them, before killing them. When the army arrived in a town the general asked for a report. His subordinate replied, “The population is subdued and terrified!” This gave the general some satisfaction. Then the subordinate continued, “In the local monastery all monks have fled, except one.”
Hearing this, the general became furious. He rushed to the monastery to meet the monk who dared defy him. When he saw the monk he pulled his sword out and pushed it towards his stomach and hissed in a low but terrifying voice, “Don’t you know who I am? Why, I could take this sword and run it through your belly without blinking my eye!”
The monk was not fazed, he replied gently, “And don’t you know who I am? I could have your sword run through my belly without blinking an eye.”
The general was awestruck. He sheathed his sword, bowed, and left without uttering another word.