“Eat of what is on earth lawful and good, and do not follow the footsteps of Satan”. (Qur’an 2:168).
Using only what is lawful and good, and abstaining from unlawful (Haram) and bad things, are among the basic principles of Islamic code of life.
In Islam, even a lawful thing becomes unlawful if it is obtained by unlawful or foul means. There is no denying that lawful methods, seem sometimes, to be slow; and people, who want to be rich overnight, resort to unlawful means. But, when all is said and done, such tactics do not benefit the offender very much.
Sometime ago a test was held in which one motorist was asked to reach a certain place as soon as possible without any regard to the traffic rules, while another was to reach there after obeying all road signs and traffic signals. The first driver violated red lights twice, nearly knocked down a pedestrian, entered a one-way road from wrong direction, just managing to avoid a serious accident, and reached the destination – 30 seconds before the second motorist. What a gain after all those dangers.
More to the point is the following episode. Hazrat Ali (A.S.) once came to a mosque where he wanted to pray. He asked a man standing nearby to guard his horse. When he came out, he had a dirham in his hand which he wanted to give that man as a reward. But he was nowhere to be seen. Hazrat Ali (A.S.) came to the horse and found that its rein was missing. He gave someone the same dirham to buy another rein.
The man went to the market, saw a man selling a used rein, and bought it for one dirham. When Hazrat Ali (A.S.) looked at it he found that it was his own rein which the supposed “guard” had stolen. He said that he had intended to give the “guard” the same, dirham as a reward, which would have been perfectly lawful for him; but his impatience turned him into a thief, and he got nothing except the same dirham. His dishonesty did not increase his wealth at all, and made him a – criminal into the bargain.