Oneness, Uniqueness of Allah (Tawheed)

Bukhari :: Book 9 :: Volume 93 :: Hadith 505

Narrated Anas:

The Prophet said, "Allah did not send any prophet but that he warned his nation of the one-eyed liar (Ad-Dajjal). He is one-eyed while your Lord is not one-eyed, The word 'Kafir' (unbeliever) is written between his two eyes."