Sand or Stone?

Two friends were walking through the desert. At some point in 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, 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 take a bath in the pond. The one who had been slapped got stuck in the mire and was in danger of drowning, but the friend saved him.

After he recovered from the near drowning, he found a stone on which he wrote,

"Today my best friend saved my life."

The friend who had first slapped and then saved his best friend asked him, "After I hurt you, you wrote in the sand and now, when I saved you, you wrote on a stone. Why?"

The friend replied,

"When someone hurts us, we should write it down in sand, where winds of forgiveness can carry it away.

"But when someone does something good for us, we must engrave it in stone where no wind can ever erase it."
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