The Samurai and The Sword

Once a samurai came to the Zen master Hakuin and asked, “Master, tell me, what's the difference between heaven and hell?”
The master, found meditating on his matted floor, was quiet for some time. At last he slowly turned and gazed at the man. He asked, "Who are you?"
“I am a samurai swordsman and a member of the emperor’s personal guard.”
“You call yourself a samurai warrior?” said Hakuin doubtfully. “Look at you, what kind of emperor would have you for a guard? You look more like a beggar!”
“What?” the samurai shot back, growing red in the face. He reached for his sword.
“Oho!” said Hakuin. “So you have a sword, do you! I bet you couldn't cut off the head of a fly with that."
The samurai could not contain himself. He drew his sword from its sheath and lifted it above the head of the old monk.
Hakuin responded quickly, “That sir, is the gate to hell.”
The samurai slowly lowered his sword, put it back in its sheath, and bowed.
“And that,” said the master, "is the gate to heaven.”