The Prophet himself was a businessman before he was appointed as a Prophet. His ability to run business prudently, by his fairness and truthful conduct in dealing with people had won him the heart of his employer, Khadijah who later offered him marriage. He advocated Muslims to follow the spirit of Prophet Daud ( David ) of hard work earned his living from his own labour . He also said that faith of a Muslim is not complete If he is not good in his profession. He said : " If you leave matters to those who are not professional you are waiting for the disaster " . If he works in the production line his products must be compatible with products of other companies or factories. In order to be marketable it must suit the taste of buyers and their standards of living. In this regard, Islam teaches not to cheat in offering the product to the market. It must be shown as it is without any publicity it does not deserve. In the life time of the Prophet, he found many cases in market places where the merchants tried to cheat the customers. The Prophet said to them : " Whoever cheated are not from amongst us ( Muslims ) " . Islam laid many regulations in the field of economy such as trade leasing , business transaction, contract and others to prevent unfair dealing within the community and in the world of business at large . What is also prevented by Islam is a monopoly and exploitation by one man or one group at the expense of the others.