It is narrated from Sayyiduna Abdullah bin Hanzalah bin al-Rahib (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "A single dirham of usury (riba) is graver in the sight of Allah than committing fornication thirty-six times."
No one narrated this hadith from Layth (may Allah have mercy on him) except Ubaydullah (may Allah have mercy on him).
Hadith Referenceالمعجم الأوسط / باب الألف / 2682
Hadith Takhrij«أخرجه الضياء المقدسي فى «الأحاديث المختارة» برقم: 229، 230، والدارقطني فى «سننه» برقم: 2845، 2843، وأحمد فى «مسنده» برقم: 22376، والبزار فى «مسنده» برقم: 3381»