Sahih Bukhari Volume 005, Book 059, Hadith Number 609.
Hadith Section/Book: Sahih Bukhari Sahih Bukhari Book 59. Military Expeditions Led by the Prophet (PBUH) (Al-Maghaazi)
Narrated By Ibn 'Umar : When we returned from (the battle of) Hunain, 'Umar asked the Prophet about a vow which he had made during the Pre-lslamic period of Ignorance that he would perform Itikaf. The Prophet ordered him to fulfill his vow.