Sunan an-Nasa'i 2077
It was narrated that Abu Hurairah said:
"The Messenger of Allah said: 'The Messenger of Allah said: 'The whole of the son of Adam will be consumed by the earth, except for the tailbone, from which he was created and from which he will be created anwe."'
أَخْبَرَنَا قُتَيْبَةُ، عَنْ مَالِكٍ، وَمُغِيرَةَ، عَنْ أَبِي الزِّنَادِ، عَنِ الأَعْرَجِ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏
"‏ كُلُّ بَنِي آدَمَ - وَفِي حَدِيثِ مُغِيرَةَ كُلُّ ابْنِ آدَمَ - يَأْكُلُهُ التُّرَابُ إِلاَّ عَجْبَ الذَّنَبِ مِنْهُ خُلِقَ وَفِيهِ يُرَكَّبُ ‏"‏ ‏.‏