Prophetic Commentary on the Qur'an (Tafseer of the Prophet (pbuh))
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.Narrated Ibn `Abbas:The last Verse (in the Qur'an) revealed to the Prophet (ﷺ) was the Verse dealing with usury (i.e. Riba)
From Sahih al-Bukhari, whose reports the scholars accept as authentic.