There was a little boy with a bad temper. His father gave him a bag of nails and told him that every time he lost his temper, he must hammer a nail into the back fence.
The first day, the boy drove 37 nails into the fence. Over time, the number dwindled. He discovered it was easier to control his temper than to hammer the nails. Finally, a day came when the boy did not lose his temper at all.
He told his father, who then suggested the boy pull out one nail for each day he kept his temper under control. Days passed, and eventually, the boy reported that all nails were gone.
The father took his son to the fence and said, "You have done well, my son. But look at the holes. The fence will never be the same. When you speak in anger, your words leave a scar just like these holes. You can stab a man with a knife and pull it out, but no matter how many times you say 'I'm sorry,' the wound remains. A verbal wound is as harmful as a physical one."