What is riba (interest), and why is it haram?

What riba actually is

The word riba means "increase" in Arabic. In the Shari'ah it carries a narrower, technical sense: an increase in specific things, in specific ways. Ibn Qudamah defines it in al-Mughni as "the increase in particular things," and al-Shanqiti in his commentary on Zad al-Mustaqni' gives the same definition — a specific increase in specific items.

The scholars divide it into two types:

• Riba al-nasi'ah (the riba of delay): this is the original and the more serious form. It is the increase charged for postponing a debt that has fallen due — the lender says "pay me more, and I will give you more time." This is the riba the Arabs practised before Islam, and it is the one the Qur'an addresses directly.
• Riba al-fadl (the riba of excess): this is the sale of one ribawi item for another of the same kind with an unequal amount — gold for gold, or wheat for wheat, with one side greater. It was prohibited as a means of blocking the road to the first type, since it contains an increase without a counter-value.

Ibn Qudamah notes that the Prophet ﷺ named six items in the hadith of 'Ubadah ibn al-Samit — gold, silver, wheat, barley, dates and salt — and that the scholars extend the ruling to other items by the same effective cause: for gold and silver, their being a medium of exchange; for foodstuffs, their being measured or weighed.

Why the scholars hold it is haram

The prohibition rests on three sources, and the scholars are unanimous on it.

The Qur'an. Allah says:

"But Allah has permitted trade and has forbidden interest."— Qur'an 2:275

And He warns those who persist:

"O you who have believed, fear Allah and give up what remains of interest, if you should be believers. And if you do not, then be informed of a war from Allah and His Messenger."— Qur'an 2:278–279

Al-Shanqiti comments that when Allah declares war on a person, that person's affair is beyond asking — Allah will afflict him in his own self, his wealth, his family and his children, and what awaits him in the Hereafter is worse.

The Sunnah. The Prophet ﷺ listed riba among the seven destructive sins:

"Avoid the seven destructive sins." They said, "O Messenger of Allah, what are they?" He said, "Associating partners with Allah, magic, killing the soul which Allah has forbidden except by right, consuming riba, consuming the wealth of the orphan, turning back on the day of battle, and slandering chaste, believing, unaware women."— Sahih al-Bukhari 2766 and Sahih Muslim 89, from Abu Hurayrah

And he ﷺ cursed not only the one who takes it but everyone involved:

"The Messenger of Allah ﷺ cursed the one who consumes riba, the one who pays it, the one who writes it down and the two who witness it, and he said: they are all alike."— Sahih Muslim 1598, from Jabir ibn 'Abdullah

The consensus. Ibn Qudamah states plainly that the Muslim community has agreed that riba is forbidden, and IslamWeb (fatwa 26870) reports the same: the Muslims in their entirety are agreed on its prohibition.

Why it is so severely prohibited

The scholars give reasons that go to the heart of what riba does to a society, not merely to the individual who profits.

• It is injustice in exchange. Al-Tuwayjiri divides financial dealings into three categories: justice, which is trade; bounty, which is charity; and injustice, which is riba. Riba is the third — wealth taken without a counter-value.
• It transfers wealth from the poor to the rich. Al-Tuwayjiri explains that riba causes enmity between people, inflates the wealth of the lender at the expense of the poor, and closes the door of charity and kindness.
• It kills the incentive to work. The one who lives on riba grows his money without effort, so he abandons trade and the industries people need. Al-Tuwayjiri notes that no one increases in riba except that his affair ends in decrease.
• It hardens the heart. The same source describes the moneylender's heart as stamped with selfishness, miserliness, constriction and hardness, and with the worship of money itself.

Ibn Taymiyyah, as quoted by Ibn 'Uthaymin, went further: no sin short of shirk has been threatened with the punishment that riba has. This is why he was so severe in blocking the means that lead to it.

Who the prohibition covers

The ruling is not limited to banks or to strangers. IslamWeb (fatwa 328363) addresses the case of a father who lends to his son and stipulates repayment with an increase: this is forbidden riba, and the one who does it is cursed. The reasoning given in Kashshaf al-Qina' is that the son's ownership of his wealth is complete and independent, so riba operates between them just as it does between strangers. Al-Sarakhsi extends the same to a slave and his master.

Ibn 'Uthaymin adds an important qualification on the curse in the hadith: it is a general statement, not a judgement on any named individual. A specific person who consumes riba may have good deeds that erase its traces, so we do not testify that any particular person is cursed — we state the ruling in general terms.

What this means in practice

• Avoid taking or paying interest. IslamWeb (fatwa 25928) states that riba is forbidden to the owner of capital, whether a bank or otherwise, and to the borrower who takes a loan with interest, whether poor or rich. Both carry sin.
• Do not assist it. The one who writes it down and the one who witnesses it are also sinful, by the generality of the texts.
• Necessity is real but narrow. IslamWeb (fatwa 18048) notes that the principle "necessities permit the prohibited" applies, but only to a genuine, extreme necessity — not to convenience. The same source advises that if buying a house requires riba, one can rent instead until Allah provides.
• Repentance is open. IslamWeb (fatwa 25928) lists five conditions of repentance: ceasing the sin immediately, regretting what has passed, resolving not to return, restoring the rights of anyone wronged, and repenting before death. The Prophet ﷺ said: "The one who repents from sin is like one who has no sin."

Key takeaways

• Riba is any stipulated increase without a lawful counter-exchange, and it is forbidden by the Qur'an, the Sunnah and the consensus of the scholars.
• It is one of the seven destructive major sins, and the Prophet ﷺ cursed the taker, the payer, the writer and the witnesses alike.
• The prohibition is not softened by family ties — a father charging his son interest is committing the same forbidden act.
• Both sides of an interest transaction carry sin, whether the party is a bank or an individual, rich or poor.
• Necessity may permit what is otherwise forbidden, but only a genuine, extreme necessity — and repentance remains available to anyone who turns back.

Further reading

• Ibn Qudamah, al-Mughni, "Kitab al-Buyu' — Bab al-Riba wa al-Sarf"
• Ibn Qudamah, al-Kafi fi Fiqh al-Imam Ahmad, "Bab al-Riba"
• Al-Shanqiti, Sharh Zad al-Mustaqni', "Bab al-Riba wa al-Sarf"

And Allah knows best.