9. The meaning, methods, and different kinds of commerce.51
It should be known that commerce means the attempt to make a profit by increasing capital, through buying goods at a low price and selling them at a high price, whether these goods consist of slaves, grain, animals, weapons, or clothing material. The accrued (amount) is called "profit" (ribh).
The attempt to make such a profit may be undertaken by storing goods and holding them until the market has fluctuated from low prices to high prices. This will bring a large profit. Or, the merchant may transport his goods to another country where they are more in demand than in his own, where he bought them. This, (again,) will bring a large profit.
Therefore, an old merchant said to a person who wanted to find out the truth about commerce: "I shall give it to you in two words: Buy cheap and sell dear.52 There is commerce for you." By this, he meant the same thing that we have just established.
God "gives sustenance. He is strong and solid." 53