Carved In Stone

One day, there are two friends who were walking through the desert . During some point of the journey they had an argument, and one friend slapped the other one in the face. The one who got slapped was hurt, but without saying anything, she bent down and wrote in the sand ' TODAY MY BEST FRIEND SLAPPED ME IN THE FACE ' .
They kept on walking until they found an abandoned oasis. However, there was a little pool so they decided yo take a bath. The one who had been slapped got stuck in the mire and began to drown, but the friend saved her . After she recovered from the near drowning, she wrote on a stone ' TODAY MY BEST FRIEND SAVED MY LIFE ' .
The friend who had slapped and then later saved her best friend asked her " After I hurt you, you wrote it in the sand and now, you write on a stone. Why ? " The friend replied " When someone hurts us we should write it down in sand where winds of forgiveness can erase it away. But when someone does something good for us , we must engrave it in stone where no wind can ever erase it " .