"高利贷"（Riba）是指以同类财物进行不等量的交换。"货币兑换"（Sarf）是指以金银的同类财物进行等量交换，或以两种不同类别的财物进行等量或有差别的交换。兑换只能在交易中发生；至于高利贷，则只能发生在买卖（Bay'u）交易、借贷（Qardh）或预付定购（Salam）之中。买卖（Al-Bay'u）是指以财物交换财物，从而实现财产的交换；这是被允许的，因为真主（SWT）说：

Riba (usury) is the practice of taking property for another property of the same type unequally. The money exchange (Sarf) is the practice of taking a property for another property from gold and silver of the same type equally, or of two different types equally or preferentially. The exchange can only take place in trade, as for usury, it can only happen in a trade (Bay’u) transaction, in a loan (Qardh) or in a Salam (forward buying). Trading (Al-Bay’u) is the practice of exchanging property for property resulting in an exchange of property; this is permitted for Allah (swt) says:

“并且安拉允许了买卖”[黄牛章：275] 又因为布哈里根据哈基姆·本·希扎姆的传述记载，安拉的使者ﷺ说：“买卖双方在未分开之前拥有撤销交易的权利。”至于萨拉姆（预付定购），是指即时交付一件商品，以换取将在未来某个特定时间交付的一件确定商品，也称为萨拉夫（赊购）。它是买卖的一种，其订立方式与买卖相同，只是使用“萨拉姆”的措辞。这是被允许的，因为安拉（SWT）说：

“And Allah has made trading lawful” [Al-Baqarah: 275] And because Bukhari reported on the authority of Hakeem Ibn Hizaam that the Messenger of Allah (pbuh) said: “The two trading parties possess the right of withdrawal (from the deal) unless they separate.” As for the Salam, this means handing over a commodity immediately for a defined commodity which is to be handed over at a specific time in the future (Ajal). Salam also known as Salaf (credit). It is one type of trading and it is contracted in the same way as the trading, but with the wording of Al-Salam. This is permitted for Allah (swt) says:

“当你们彼此约定一个期限的借贷时，你们就应当把它写下来。”{黄牛章 282} 伊本·阿拔斯说：“我作证，真主“至尊至大”允许并准许了有固定未来期限的预付借贷（赊购预付），然后他诵读了这节经文：”

“When you contract a debt for a fixed period, write it down” [Al-Baqarah: 282] Ibn Abbas said: “I bear witness that the guaranteed Salaf (borrowing), to a fixed future date, has been made lawful and allowed by Allah “Azza Wa Jall”, then He recited the verse:

“当你们以约定的期限进行借贷时，应当把它写下来。” [Al-Baqarah: 282]

“When you contract a debt for a fixed period, write it down” [Al-Baqarah: 282]

而且,因为两位舍赫(即布哈里和穆斯林)根据伊本·阿拔斯的传述说:"安拉的使者ﷺ来到麦地那时,人们在两三年间借贷椰枣,于是他ﷺ说:'若有人借出任何东西,就应当以已知的量或已知的重量,并约定已知的期限。'"至于借贷(Qardh),它是一种预支(Salaf),即把财产交给某人,之后再由其归还,这是合法的。穆斯林根据阿布·拉菲仪的传述说:"安拉的使者ﷺ向一个人借了一头幼驼,之后他ﷺ收到了天课形式的骆驼。于是他ﷺ命阿布·拉菲仪把幼驼还给那个人;阿布·拉菲仪回来说:'我只找到一头四岁的骆驼。'他ﷺ说:'把它给他吧,因为最好的人就是以最好的方式偿还债务的人。'"伊本·哈班根据伊本·麦斯欧德的传述说:安拉的使者ﷺ说:"任何穆斯林若两次借给另一位穆斯林,其中一次都会为他被记为施舍。"还因为已经确定安拉的使者ﷺ曾经借贷。

Also because the two Sheikhs (i.e. Bukhari & Muslim) reported on the authority of Ibn Abbas who said: “The Messenger of Allah (pbuh) arrived in Madinah while people were lending and borrowing dates over two or three years, so He (pbuh) said: ‘If any of you lends anything, let it be in a known measure or a known weight and for a known period of time.”’ As for the Qardh (loan), it is a type of Salaf, which is to give property to someone in order to restore it from Him later and this is lawful. Muslim reported on the authority of Abu Rafi’i “that the Messenger of Allah (pbuh) borrowed a young camel from a man, then He received Sadaqah in the form of camels. So He (pbuh) ordered Abu Rafi’i to give the man his young camel; Abu Rafi’i came back to Him and said: ‘I only found a four year old camel.’ Upon this He (pbuh) said: ‘Give it to him, for the best people are those who pay back their debt in the best manner.”’ Ibn Hibban reported on the authority of Ibn Mas’oud that the Messenger of Allah (pbuh) said: “No Muslim would give another Muslim a loan twice, except that one would be written for Him as charity.” Also because it has been established that the Messenger of Allah (pbuh) used to borrow.