A very strong woodcutter asked for a job with a local timber merchant. He was determined to do his best. The woodcutter's boss gave him an axe and showed him an area in which to work.
The first day the woodcutter brought in 18 trees. The boss congratulated him and encouraged him to go on with it. The woodcutter vowed to work harder.
He tried harder the next day but brought in only 15 trees.
The third day he tried even harder but brought in only 10 trees.
Day after day the woodcutter was bringing in less and less trees. He went to the boss and apologized, saying he must be losing his strength. The boss asked the woodcutter when was the last time he sharpened his axe. He exclaimed sharpen! Why I have had no time to sharpen my axe because I have been so busy cutting down trees.