Oneness, Uniqueness of Allah (Tawheed)
Bukhari :: Book 9 :: Volume 93 :: Hadith 597
Narrated Abu Huraira:
Allah's Apostle said, "A man who never did any good deed, said that if he died, his family should burn him and throw half the ashes of his burnt body in the earth and the other half in the sea, for by Allah, if Allah should get hold of him, He would inflict such punishment on him as He would not inflict on anybody among the people. But Allah ordered the sea to collect what was in it (of his ashes) and similarly ordered the earth to collect what was in it (of his ashes). Then Allah said (to the recreated man ), 'Why did you do so?' The man replied, 'For being afraid of You, and You know it (very well).' So Allah forgave him."