كتاب الْمَسَاجِدِ وَمَوَاضِعِ الصَّلاَةِ
5  
The Book of Mosques and Places of Prayer
(24)
Chapter: It is recommended to seek refuge with Allah from the punishment of the grave, the punishment of hell, the trials of life and death, the tribulation of the Dajjal and from sin and debt between the tashah-hud and the taslim
(24)
باب اسْتِحْبَابِ التَّعَوُّذِ مِنْ عَذَابِ الْقَبْرِ ‏
Sahih Muslim 585

Abu Huraira reported. I heard the Messenger of Allah (ﷺ) seeking refuge from the torment of the grave after this (after the revelation).

وَحَدَّثَنِي هَارُونُ بْنُ سَعِيدٍ، وَحَرْمَلَةُ بْنُ يَحْيَى، وَعَمْرُو بْنُ سَوَّادٍ، قَالَ حَرْمَلَةُ أَخْبَرَنَا وَقَالَ الآخَرَانِ، حَدَّثَنَا ابْنُ وَهْبٍ، أَخْبَرَنِي يُونُسُ، عَنِ ابْنِ شِهَابٍ، عَنْ حُمَيْدِ بْنِ عَبْدِ الرَّحْمَنِ، عَنْ أَبِي هُرَيْرَةَ، قَالَ سَمِعْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم بَعْدَ ذَلِكَ يَسْتَعِيذُ مِنْ عَذَابِ الْقَبْرِ ‏.‏
Reference : Sahih Muslim 585
In-book reference : Book 5, Hadith 158
USC-MSA web (English) reference : Book 4, Hadith 1213
  (deprecated numbering scheme)