Two friends were walking through the desert. At some point they had an argument, and one friend slapped the other in the face. The one who got slapped was hurt, but without saying anything, wrote in the sand:
"TODAY MY BEST FRIEND SLAPPED ME IN THE FACE." They kept on walking until they found an oasis, where they decided to go for a swim. The one who had been slapped started to drown, but his friend saved him. After he recovered from the near drowning, he wrote on a stone:
"TODAY MY BEST FRIEND SAVED MY LIFE." The one who had first slapped and later saved his friend said, "After I hurt you, you wrote in the sand and now, you write on a stone, why?" His friend replied: "When a friend hurts us we should write it down in sand where the winds of forgiveness can erase it away. But, when a friend does something good for us, we should engrave it in stone where no wind can ever erase it."