Sahih al-Bukhari 4544
Sahih al-Bukhari · Book 65: Prophetic Commentary on the Qur'an (Tafseer of the Prophet (pbuh)) · "And be afraid of the Day when you shall be brought back to Allah.. ." (V.2:281)
Narrated Ibn `Abbas:
حَدَّثَنَا قَبِيصَةُ بْنُ عُقْبَةَ ، حَدَّثَنَا سُفْيَانُ ، عَنْ عَاصِمٍ ، عَنِ الشَّعْبِيِّ ، عَنِ ابْنِ عَبَّاسٍ ـ رضى الله عنهما ـ قَالَ آخِرُ آيَةٍ نَزَلَتْ عَلَى النَّبِيِّ صلى الله عليه وسلم آيَةُ الرِّبَا.
The last Verse (in the Qur'an) revealed to the Prophet (ﷺ) was the Verse dealing with usury (i.e. Riba).