Oneness, Uniqueness of Allah (Tawheed)

Bukhari :: Book 9 :: Volume 93 :: Hadith 600

Narrated Anas:

I heard the Prophet saying, "On the Day of Resurrection I will intercede and say, "O my Lord! Admit into Paradise (even) those who have faith equal to a mustard seed in their hearts." Such people will enter Paradise, and then I will say, 'O (Allah) admit into Paradise (even) those who have the least amount of faith in their hearts." Anas then said: As if I were just now looking at the fingers of Allah's Apostle.