In Islamic history, awareness of the importance of money in an economic system has emerged long before economics was recognized as a separate discipline. The role of money in Islamic economics has been discussed by Iman al-Ghazali (1058-1111 AD) in his book famous, þIhya Ulum al-Din. According to him, people just need money as a broker / exchange (medium of exchange) to purchase goods and services. Meanwhile, Ibn Taymiyya (1263) mentions that the money was not only functions as a medium of exchange, but he also serves as a tool for determining the value (measurement of value). Finally, in discussing the role of money in the economy, agreed with Ibn Qayyim al-Ghazali, Ibn Khaldun as it is more likely to agree with the opinion of Ibn Taymiyya.

Because there are economic instruments that are both conventional instruments or institutional policy that is inconsistent with the teaching of the Quran and the Hadith, the function and role of money in the economy of conventional and Islamic economics is different. Because the fundamental reason the economic functions of money in Islamic and conventional economics is different is that the Islamic economic system, interest (riba), gambling (gambling) and the elements are not clear, gharar (uncertainty) is forbidden religion. While conventional economic view of all these elements as a normal and legal.

In conventional economics, JM Keynes (1936) in his famous book, A General Theory of Employment, Interest and Money mengemukan a theory about the demand for money, known as liquidity preference (liquidity preference). This liquidity preference theory states that there are three main motives that determine the amount of demand for money in an economy, namely: the motive transaction (transaction motive); motive case (precautionary motive); and speculative motives (Speculative motive).

Transactions motive is defined as a motive for the demand for money necessary for the needs of a transaction. Because these transactions are usually done by individuals and businessman, the JM Keynes divides this transaction motive in (a) the motives of income (income motive), and (b) the motives of business (business motive). Meanwhile, in case the motive is a motive for holding money in order to anticipate the productions that can not be predicted in the future. In conventional economics, this motif dipengarahui by individual income levels and interest rates. Meanwhile, demand for money by speculation that the motive is to avoid deterioration of the capital value (capital value) due to decreased economic activity. To avoid this loss, the businessman used to invest money (capital) in the stock markets whose profits were largely determined by the difference in interest rates.

So we can clearly see that the first two motifs demand for money, ie the transaction motive and the motive is to guard berkaitang money directly to function as a medium of exchange (the tool of exchange) in an economy. Meanwhile, speculation over the motive is closely related to function as a store of money or property prices (store of value or wealth). When we think komparasikan between Islamic economic thinkers with Keynes's opinion above, it was clear that unless the motives of the money to speculate, the motive for having more money is approved by the economic thinkers of Islam, as stated above.

We know that the motive for this speculation is intended to scoop a profit and accumulate wealth by memamfaatkan rate changes from time to time. Looking at the characteristics and the way it is practiced in the speculation business world that involve interest (interest) to justify all means, promote the value of greed (greediness) without regard to the values of justice, it is expressly opposed to Islamic motifs of this speculation. One example of this motif is the act of monopoly (ihtikar). In a monopoly of goods and services as one act of speculation, Imam al-Ghazali distinguishes between the monopoly at the time of shortages (shortages), or the economy in the famine and at the excess (surplus) of goods and services. Shortages in the state, monopolistic practices are very much against the economic values of Islam.

Meanwhile, the Islamic economic thinkers did not see action as a monopoly on goods and services in a surplus situation as something that acts contrary to moral values and Islamic norms. This is because at the time of the excess supply of goods and services in the market, monopoly action will not affect the price of goods and services that will not endanger the welfare of the people. So it is clear to us that the motive of this speculation is contrary to the values of justice, because in addition to involving interest, it also involves elements of gambling (gambling) and also involves gharar elements.

As mentioned earlier, both the motive and the motive for the transaction in case it is not seen as a motive for the demand for money as opposed to the values and norms of Islam. But this does not mean that in a transaction, one that could take its own course with violating the provisions of God Almighty, such as manipulation, transactions of illegal goods, transactions involving interest, and monopoly. The motive of this transaction should be based on the concept of Islamic transactions. Meanwhile, in case the motive is a motive of money demand is highly recommended that Islam, as long as that motive sahaja not solely motivated to reap maximum benefit, perhaps, by exploiting differences in interest rates and saving money from places mengelurkan deposits (banks). Because of this motive is a motive for someone to save money for the sake of the future, especially in the face of economic difficulties that can not be dijangkakan, then this pattern is in accordance with the values of humanity and consideration to help others (altruistic consideration).

This motif is very useful not only to relieve himself, but also to help ease the burdens of others when facing economic disaster. However, the offered assistance to alleviate other people should not in the form of loan interest, but preferably in an interest-free assistance bentuan, Qard al-Hasan.

In addition, please note that Islam forbids treating the money as the goods (commodity) that can be bought and sold. In Islam, money is not identical with commodity that can be traded for the purpose of making profit (In Islam, money is not identical to items that can be traded in order to profit). Islam only see money as a medium of exchange, intermediary devices, and tools to determine the value, not as goods bought and sold. This means that Islam does not justify the money traded on the Foreign Exchange market (VALAS) with the purpose of speculation and enrich themselves.

Memperjualbelikan advantage in money markets Foreign Currency sourced from the difference in purchase price and selling price and interest rate differences between one country to another country where the Foreign Currency is traded against Islamic values. For example, we bought the U.S. dollar using IDR, and then sell the U.S. dollar to buy the British pound sterling, pound sterling and later sold to buy Deutchmark Germany, and eventually sold to re Deutchmark buy rupiah, and so on. From this sale process, which is often referred to Arbitraging, usually gains or losses on the can is not worth the sacrifices made and the time required. It may be that in time the shortest possible time, as the case of George Soros, who has been blamed for the primary application of the monetary crisis in the greater part of the East Asian country recently, the benefits can memperjualbelikan money with Foreign Currency market is berbilion-milliard. Soros is due to the action, not the few countries that fragile economic fundamentals particularly Indonesia, the people must suffer because of the economic crisis that hit. This is the reason why Islam does not justify the money is treated the same as free goods bought and sold, as practiced in Western economies.

Based on the above explanation, then we can see that the prohibition of "interest" (usury) in Islamic economics cause not all the functions of money in the economy can be implemented in the conventional economic system of Islam. The involvement of interest, gambling, and gharar juhalah the motive of money demand has led to speculate this motif strongly opposed by Islam. Meanwhile, two other motives, motives for the transactions demand for money and in case was not regarded as a motive for holding money is contrary to Islamic values as far as the elements of riba does not motivate them in the second motive was money demand. Unlike in conventional economics, Islamic economics strongly opposes it to be treated the same as the goods (commodities) which can be bought and sold are intended solely for profit.