That during the Hajj in which the Prophet ﷺ had made Abu Bakr As Siddiq as chief of the, Hajj before the Hajj-ul-Wida,' on the day of Nahr, Abu Bakr sent him along with a group of persons to announce to the people. "No pagan is permitted to perform Hajj after this year, and nobody is permitted to perform the Tawaf of the Kaʿba naked."  

أَنَّ أَبَا بَكْرٍ الصِّدِّيقَ ؓ بَعَثَهُ فِي الْحَجَّةِ الَّتِي أَمَّرَهُ النَّبِيُّ ﷺ قَبْلَ حَجَّةِ الْوَدَاعِ يَوْمَ النَّحْرِ فِي رَهْطٍ يُؤَذِّنُ فِي النَّاسِ لاَ يَحُجُّ بَعْدَ الْعَامِ مُشْرِكٌ وَلاَ يَطُوفُ بِالْبَيْتِ عُرْيَانٌ  

The last Sura which was revealed in full was Baraa (i.e. Sura-at-Tauba), and the last Sura (i.e. part of a Sura) which was revealed was the last Verses of Sura-an-Nisa':-- "They ask you for a legal decision. Say: Allah directs (thus) About those who have No descendants or ascendants As heirs." (4.177)  

آخِرُ سُورَةٍ نَزَلَتْ كَامِلَةً بَرَاءَةٌ وَآخِرُ سُورَةٍ نَزَلَتْ خَاتِمَةُ سُورَةِ النِّسَاءِ {يَسْتَفْتُونَكَ قُلِ اللَّهُ يُفْتِيكُمْ فِي الْكَلاَلَةِ}