Two great Arab merchants, Amir names and Farid, were and whenever they made their trips to a market where they sold their goods, they went together, each with his Caravan and his slaves employees. One trip, to pass along a raging river, Farid decided to bathe because it was very hot. At the given moment, distracting, was dragged by the current. Amir, seeing that his close friend was in life-threatening, jumped to the waters and, with unprecedented effort, couldn't save him. After this episode, Farid called one of his slaves and ordered him to record a rock there, a phrase that reminded everyone of what happened. To return, went through the same place where they stopped for quick home. As they talked, had a little discussion and Amir changing slapped Farid. This approached the banks of the river and, with a wand, wrote in the sand. The slave who was tasked to write in stone the thanks of Farid, asked him: my Lord, when you were saved, sent record that made a rock and now write on the sand the injury received. Why are you doing so? Farid answered him:-acts of kindness, love and selflessness should be written on the rock so that all those who have opportunity to take notice of them, seek to emulate them. On the contrary, however, when we receive an insult, we must write it in the sand near the water for it to go away, taken with the tide, so that no one becomes aware of it and, most of all for any heartache disappear promptly in our heart!