Oneness, Uniqueness of Allah (Tawheed)
Bukhari :: Book 9 :: Volume 93 :: Hadith 641
Narrated 'Imran:
I said, "O Allah's Apostle! Why should a doer (people) try to do good deeds?' The Prophet said, "Everybody will find easy to do such deeds as will lead him to his destined place for which he has been created.'