Sahih Muslim , Hadith 2370 ⓘ
Abu Huraira reported Allah's Messenger as having said that Ibrahim (as) circumcised himself with the help of an adze when he was eighty years old.
حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، حَدَّثَنَا الْمُغِيرَةُ، - يَعْنِي ابْنَ عَبْدِ الرَّحْمَنِ الْحِزَامِيَّ - عَنْ أَبِي الزِّنَادِ، عَنِ الأَعْرَجِ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " اخْتَتَنَ إِبْرَاهِيمُ النَّبِيُّ عَلَيْهِ السَّلاَمُ وَهُوَ ابْنُ ثَمَانِينَ سَنَةً بِالْقَدُومِ " .
also referenced under: Book 43, Hadith 199 (In-Book) & Book 30, Hadith 5844 (USC-MSA)