Two friends were walking through the desert. 

During the journey, they had an argument and one friend slapped the other in the face.

The one who was slapped was hurt.  Without saying anything, she wrote in the sand,

                Today, my best friend slapped me in my face.

They kept on walking until they found an oasis where they decided to take a bath.

The one who had been slapped got stuck in the mire and started to drown but was saved by their friend.

After recovering from the near drowning, she wrote on a stone,

                Today, my best friend saved my life.

The friend who had slapped and saved her best friend asked, “After I hurt you, you wrote in the sand but now you write on a stone.  Why?”

The friend replied, “When someone hurts us, we should write it down in sand where the winds of forgiveness can blow it away.  When someone does something good for us, we must engrave it in stone where no wind can erase it.”