The Messenger of Allah ﷺ said, "Usury consists of seventy sins, the least of which is equivalent to a man having intercourse with his mother."
حدثنا عبد الله بن سعيد حدثنا عبد الله بن إدريس عن أبي معشر عن سعيد المقبري
قال رسول الله ﷺ الربا سبعون حوبا أيسرها أن ينكح الرجل أمه
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[Hasan]. Busiri said, this isnad is daif. Abu Mashar is Najih bin Abdul-Rahman, and there is agreement on classifying him as daif. It has a strong corroborating narration in Ibn Jarud, no. 647. See also the following hadith.