SHAFAQNA – Usually those who lie, do so for two reasons: Either for the sake of attracting the benefits or to ward off the losses; these are the roots of lying. A person lies when there is a fear of losing benefits or profits; for example for the sake of not losing a customer, a person lies. Or on the hand, in order to ward the loss, a person has the fear of losing benefits; this is a fear of attracting the loss, so to repel the loss is also the reason for lying. Therefore, the first case is for attracting benefits and the second to ward off the losses. But a believer even if he/she has the fear of incurring loss, still tells the truth.
Source: The website of Ayatollah Sheikh Mojtaba Tehrani