Abu Dawud Book 2, Hadith Number 1380.
Chapter : The tradition that lailat alqadr falls during the last seven nights of ramadhan.
Narated By Ibn ‘Umar : The Apostle of Allah (PBUH) said: Seek lailat al-qadr in the last seven nights.
Narated By Ibn ‘Umar : The Apostle of Allah (PBUH) said: Seek lailat al-qadr in the last seven nights.