Narrated Ibn `Abbas:
The last Verse (in the Qur'an) revealed to the Prophet (ﷺ) was the Verse dealing with usury (i.e. Riba). (JA)
USC-MSA web (English) reference: Vol. 6, Book 60, Hadith 67 (JA)
Arabic reference (JA): Book 65, Hadith 4544 (JA)