Oneness, Uniqueness of Allah (Tawheed)

Bukhari :: Book 9 :: Volume 93 :: Hadith 476

Narrated Ibn Umar:

The Prophet said, "The keys of the unseen are five and none knows them but Allah: (1) None knows what is in the womb, but Allah: (2) None knows what will happen tomorrow, but Allah; (3) None knows when it will rain, but Allah; (4) None knows where he will die, but Allah (knows that); (5) and none knows when the Hour will be established, but Allah."