Sahih al-Bukhari 4814
Sahih al-Bukhari · Book 65: Prophetic Commentary on the Qur'an (Tafseer of the Prophet (pbuh)) · The Statement of Allah the Most High: "And the Trumpet will be blown, and all who are in the heavens and all who are on earth will swoon away, except him whom Allah wills..." (V.39:68)
Narrated Abu Huraira:
حَدَّثَنَا عُمَرُ بْنُ حَفْصٍ ، حَدَّثَنَا أَبِي قَالَ، حَدَّثَنَا الأَعْمَشُ ، قَالَ سَمِعْتُ أَبَا صَالِحٍ ، قَالَ سَمِعْتُ أَبَا هُرَيْرَةَ ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ " بَيْنَ النَّفْخَتَيْنِ أَرْبَعُونَ " . قَالُوا يَا أَبَا هُرَيْرَةَ أَرْبَعُونَ يَوْمًا قَالَ أَبَيْتُ. قَالَ أَرْبَعُونَ سَنَةً قَالَ أَبَيْتُ. قَالَ أَرْبَعُونَ شَهْرًا. قَالَ أَبَيْتُ، وَيَبْلَى كُلُّ شَىْءٍ مِنَ الإِنْسَانِ إِلاَّ عَجْبَ ذَنَبِهِ، فِيهِ يُرَكَّبُ الْخَلْقُ .
The Prophet (ﷺ) said, "Between the two blowing of the trumpet there will be forty." The people said, "O Abu Huraira! Forty days?" I refused to reply. They said, "Forty years?" I refused to reply and added: Everything of the human body will decay except the coccyx bone (of the tail) and from that bone Allah will reconstruct the whole body.