It is narrated from Hazrat Abdullah bin Hanzalah (may Allah be pleased with him) that the Holy Prophet (peace and blessings be upon him) said: The one dirham of usury which a person consumes knowingly is a greater sin than committing adultery thirty-six times.
Hadith Referenceمسند احمد / مسند الأنصار رضي الله عنهم / 21957
Hadith Gradingحکم دارالسلام:ضعيف مرفوعا، صحيح موقوفا على كعب الأحبار