There were two friends who were walking across a desert. While they were walking they got into an ugly argument and out of anger one of them slapped the other on the face. The one who was slapped, though was hurt he did not said anything and quietly wrote over the sand "I am hurt because today my friend hit me n my face". They resumed walking and kept walking until they came across an oasis. They decided to take bath in the oasis then. While they were taking bath the one who had got slapped started drowning. The other friend came to his rescue and saved him. After he got rescued, he wrote on the stone "Today I was saved by my best friend".
The other friend asked him, "Why did you write on the sand when I slapped you while you wrote on the stone when I saved you?" Upon this, the other friend replied that its better we write on sand when your friend hurts you as it will be gone with the wind but write it on stone when your friend does something good to you so that it could be engraved forever.