On the origin of money has three important functions, namely as a medium of exchange, store of value, and measuring the value of a commodity. However, with interest menyebarluasnya system in the current financial transaction, the function of money has grown into a commodity. The function of money as a commodity is supported by several contemporary financial theories such as the Loanable Funds Theory. In this theory of interest (interest) is considered as the price of the funds available for lending (loanable funds), which became one variable that affects the level of supply (supply of) and demand (demand for) of the loanable funds. Based on the above theory, it can be concluded that the supplier of loanable funds would be willing to lend money to the borrower if the borrower is only willing to pay back the loan in an amount greater than the principal. The difference between the amount due to the principal borrower and that is what is called interest. By contract, the price (interest) is to pay the borrower under any circumstances (the borrower's business profits or losses) to the lender, because the lender has considered selling a commodity called money.

Here is clearly seen that in the current financial system right now, money is regarded as a tradable commodity. This is in contrast with Islamic views who do not accept the functions of money as a commodity. That's because money does not qualify as a commodity. According to Sheikh Muhammad Taqi Usmani, an expert in Islamic finance Shariah, there are at least 3 factors that distinguishes the money to commodities. Firstly, money has no utility instrinsk (intrinsic utility). In contrast to commodities, money can not be eaten, worn, or used directly. Money can be exchanged only with a commodity, and commodities that will be eaten, worn or used. In economic terms, money only has value in exchange as commodities having value in exchange and value in use at once.

Second, money does not need the quality to determine its value, in terms of paper currency USD 100.000 an old issue of paper money in 2007 with a new Rp 100.000 published in 2009 has the same purchasing power. Another case with commodities, for example, output of the Honda Jazz Honda Jazz 2007 to January 2009 the output has a different price. This indicates a difference in quality between the two cars on top of which reflected the value and the price difference.

Third, the money does not require specification of the validity of transactions, while commodities have specific properties when the validity of transactions. For example, if we want to buy the goods we will choose the things we want to taste us, like color, other complementary accessories. That is, if the seller offers the same goods but they were not in accordance with our tastes may be we will refuse. But it is different with the money that is not specific. For example, for the payment of monthly electricity bills amounting to Rp 300,000. we can pay these bills by using three pieces of money USD $ 100,000 or four pieces of money Rp 50,000 plus one sheet of Rp 100,000 and even we can pay these bills with three hundred pieces of Rp 1,000. For the recipient there will be no difference in the value of the three ways above payment.

There is one additional difference between commodity money, especially with fiat money we use today. Paper money (fiat money) to current has no intrinsic value (intrinsic value). Paper money became legal tender by law issued by a country that declared the validity of the money. This shows that the acceptance of paper money as a means of payment is only due to the government trust factor that ensures the validity of these bills. That is, if the trust is lost or reduced the value of the money will be weakened (terdepresisasi) due to more people off, by selling money, than to have it. Because obviously, have no intrinsic value.

However, it should be also stressed here that fiat money is a legitimate money on the side of the sharia. The author does not agree with the view that gold is only valid at the shari'a. Indeed, the true gold is the money the best and most stable in value, and if we can re-use gold as a standard of value for money, of course, the world's financial system would be much better. However, claims that only gold or silver are recognized Islam as the money and gold and silver but it is not legitimate, this is an excessive claim. The proof, the Caliph Umar never meant to make the camel as a currency, but then was advised not to do it, because eventually the camel will be vanished from life. So is Imam Malik once said that if people make the animal skin as a currency, he undoubtedly would prohibit selling such animal skins but with cash and may not be tertangguh. Although today we are eager to return to the gold as the standard currency value, we should not be excessive and extreme by saying that fiat money is forbidden. Proscribe the same kosher is bad in Islam to justify the unlawful. If unlawful fiat money, a dowry of course we become invalid, and our marriage is not valid, then our children are also to be a bastard. Is not that logical consequence of the said fiat money is forbidden? And Allaah knows best.