Volume 2 · Book 23 · Hadith 458
Narrated Musa bin 'Uqba: (From the daughter of Khalid bin Sa id bin Al-'Asi) who said that she had heard the Prophet seeking refuge with Allah from the punishment in the grave.
— Sahih Bukhari, Volume 2, Book 23: Funerals (Al-Janaa'iz), Hadith #458