Good Manners and Form (Al-Adab)
Bukhari :: Book 8 :: Volume 73 :: Hadith 232
Narrated 'Aisha:
Some people asked Allah's Apostle about the fore-tellers. Allah's Apostle said to them, "They are nothing (i.e., liars)." The people said, 'O Allah's Apostle ! Sometimes they tell something which comes out to be true." Allah's Apostle said, "That word which comes to be true is what a jinx snatches away by stealing and then pours it in the ear of his fore-teller with a sound similar to the cackle of a hen, and then they add to it one-hundred lies."