From Nyanaponika Thera

Suppose a man has been wounded by an arrow thickly smeared with poison, and his friends and companions, relatives and kinsmen call a physician, a surgeon. And the physician, the surgeon, widens the wound with his knife and searches for the arrow point with the probe. Having found the arrow point, he extracts it and completely removes the poison until he thinks that nothing of it is left... This simile have I given to make the meaning clear. And its significance is this:

'The wound' is a name for the six internal sense bases.
'The poison' is a name for ignorance.
'The arrow' is a name for craving.
'The probe' is a name for mindfulness.
'The knife' is a name for noble wisdom.
'The physician, the surgeon' is a name for the Perfect One, the Holy One, the Fully Enlightened One." - Sutta excerpt


- The Heart of Buddhist Meditation (Nyanaponika Thera)