Oneness, Uniqueness of Allah (Tawheed)

Bukhari :: Book 9 :: Volume 93 :: Hadith 596

Narrated Abu Huraira:

Allah's Apostle said, "Allah said, 'I am to my slave as he thinks of Me, (i.e. I am able to do for him what he thinks I can do for him). (See Hadith No. 502)