Sahih Bukhari
Sahih Bukhari Volume 005, Book 059, Hadith Number 290.
Hadith Section/Book: Sahih Bukhari Sahih Bukhari Book 59. Military Expeditions Led by the Prophet (PBUH) (Al-Maghaazi)
Narrated By Ibn Abbas: The believers who failed to join the Ghazwa of Badr and those who took part in it are not equal (in reward).