Short answer
The authentic hadith make riba one of the seven destroying sins. The Prophet ﷺ cursed the one who takes it, the one who pays it, the one who writes it and its witnesses, and said they are all the same. He saw its consumer punished in a river of blood, and said that riba, however much it grows, ends in loss.
Riba is haram by the Quran, the Sunnah and the consensus of the Muslims, and it is a major sin (kabirah). Taking, paying, recording and witnessing it are all sinful. Whoever holds it to be halal, knowing the texts, denies something agreed on in the religion.
The four schools agree on this.
Explanation
The main authentic hadith on riba:
- One of the seven destroyers. The Prophet ﷺ said, "Avoid the seven destroying sins," and listed consuming riba among them, alongside shirk, magic and killing (Bukhari).
- All four are cursed. He cursed the consumer of riba, the one who pays it, its scribe and its two witnesses, and said, "They are all the same" (Muslim).
- The river of blood. In a dream shown to him, he saw a man swimming in a river of blood, and each time he came to the bank a stone was thrown into his mouth. He was told this was the consumer of riba (Bukhari).
- It ends in loss. "No one increases his wealth through riba except that his affair ends in scarcity" (Ibn Majah, graded sahih).
- Cancelled at the Farewell Pilgrimage. He declared the riba of the Jahiliyyah abolished, starting with that owed to his own uncle al-Abbas (Muslim).
- The six items. Gold, silver, wheat, barley, dates and salt must be exchanged like for like, hand to hand (Muslim), the basis of the rules of exchange.
Two other well-known narrations compare the least of riba's forms to grave sexual sins, one in Sunan Ibn Majah and one in Musnad Ahmad. Hadith scholars differ about their chains, so this page does not rely on them. The authentic texts above are enough to show how serious riba is.
The Quran is even sharper: those who will not give up riba are told to expect "war from Allah and His Messenger" (2:279). See What does the Quran say about riba?, What is riba? and Why is interest haram? The four schools agree on all of this.
The evidence
Quran, Surah Al-Baqara 2:279
فَإِن لَّمْ تَفْعَلُوا۟ فَأْذَنُوا۟ بِحَرْبٍۢ مِّنَ ٱللَّهِ وَرَسُولِهِۦ ۖ وَإِن تُبْتُمْ فَلَكُمْ رُءُوسُ أَمْوَٰلِكُمْ لَا تَظْلِمُونَ وَلَا تُظْلَمُونَ ﴿٢٧٩﴾
And if you do not, then be informed of a war [against you] from Allah and His Messenger. But if you repent, you may have your principal - [thus] you do no wrong, nor are you wronged.
No other sin in the Quran carries this warning.
Quran, Surah Al-Baqara 2:276
يَمْحَقُ ٱللَّهُ ٱلرِّبَوٰا۟ وَيُرْبِى ٱلصَّدَقَٰتِ ۗ وَٱللَّهُ لَا يُحِبُّ كُلَّ كَفَّارٍ أَثِيمٍ ﴿٢٧٦﴾
Allah destroys interest and gives increase for charities. And Allah does not like every sinning disbeliever.
Riba removes blessing from wealth.
Sahih al-Bukhari 2766
Sahih... اجتنبوا السبع الموبقات ...
"Avoid the seven destroying sins."
Consuming riba is named among them.
Sahih Muslim 1598
Sahih... آكل الربا وموكله وكاتبه وشاهديه وقال هم سواء ...
"The one who consumes riba, the one who pays it, its scribe and its two witnesses; and he said, they are all the same."
Everyone who takes part in a riba contract shares the sin.
Sahih al-Bukhari 2085
Sahih... فقال الذي رأيته في النهر آكل الربا ...
"He said: the one you saw in the river is the consumer of riba."
The Prophet ﷺ was shown the punishment of the consumer of riba in a river of blood.
Sunan Ibn Majah 2279
Grading to be checked... ما أحد أكثر من الربا إلا كان عاقبة أمره إلى قلة ...
"No one increases through riba except that the end of his affair is scarcity."
Riba removes blessing from wealth.
Where the ruling is recorded
- al-Hidaya, Kitab al-Buyu', Bab al-Riba. Definition and types of riba in the Hanafi school.
- Bada'i al-Sana'i, Kitab al-Buyu', on the conditions free of riba. Reasoning behind the prohibition.
Checked by our team. For a more accurate answer to your own situation, consult a scholar. Quran translation by Sahih International. Hadith Arabic from the standard editions of the six books and the Muwatta, with gradings as recorded there; the English is our own rendering. Spotted a mistake? Tell us.