O darlings of your fathers, learn the trade because property and riches of the world are not to be relied upon; also silver and gold are an occasion of danger because either a thief may steal them at once or the owner spend them gradually; but a profession is a living fountain and permanent wealth; and although a professional man may lose riches, it does not matter because a profession is itself wealth and wherever you go you will enjoy respect and sit on high places, whereas those who have no trade will glean crumbs and see hardships. سعدی شیرازی Sa'di Shirazivia.