Two friends were traveling together from town to town...one of them fell into a river, and the other leaped in and saved him from drowning. The friend who had almost drowned had his servants carve these words on the large rock nearby: "Traveler! In this place, Nagib risked his life and saved the life of his friend Mussa."
The friends then resumed their journey-- only to find themselves, on the return trip, at the very spot where one had saved the life of the other. As they sat and spoke, a difference of opinion turned into a quarrel. Words were exchanged and the one who had almost drowned was hit in the face by his friend. He picked himself up, took a stick, and wrote these words in the sand: "Traveler! In this place, Nagib, in a trivial argument broke the heart of his friend Mussa."
Mussa was asked by one of his men why he would carve the story of his friend's heroism in stone, but tell the story of his cruelty only in the sand. He responded, "I will always cherish the memory of how my friend Nagib saved me in a time of danger. But the grave injury he just gave me- it is my hope that I will forgive him for it, even before the words fade from the sand."