Sahih Muslim , Book 11, Hadith 3941 (USC-MSA) ⓘ
Abu Ishaq said that he heard al-Bara' b. 'Azib (Allah be pleased with him) say: The last complete sura revealed (in the Holy Qur'an) is Sura Tauba (i e. al-Bara'at, ix.), and the last verse revealed is that pertaining to Kalala.
حَدَّثَنَا إِسْحَاقُ بْنُ إِبْرَاهِيمَ الْحَنْظَلِيُّ، أَخْبَرَنَا عِيسَى، - وَهُوَ ابْنُ يُونُسَ - حَدَّثَنَا زَكَرِيَّاءُ، عَنْ أَبِي إِسْحَاقَ، عَنِ الْبَرَاءِ، أَنَّ آخِرَ، سُورَةٍ أُنْزِلَتْ تَامَّةً سُورَةُ التَّوْبَةِ وَأَنَّ آخِرَ آيَةٍ أُنْزِلَتْ آيَةُ الْكَلاَلَةِ .
also referenced under: Book 23, Hadith 15 (In-Book) & Hadith 1618 (Reference)