Sahih Bukhari Volume 003, Book 032, Hadith Number 239.
Hadith Section/Book: Sahih Bukhari Sahih Bukhari Book 32. Praying at Night In Ramadhan (Taraweeh)
Narated By Ibn 'Abbas : Allah's Apostle said, "The Night of Qadr is in the last ten nights of the month (Ramadan), either on the first nine or in the last (remaining) seven nights (of Ramadan)." Ibn 'Abbas added, "Search for it on the twenty-fourth (of Ramadan)."