Sahih Bukhari Volume 9, Book 86, Hadith Number 97.

Narrated By Um Salama : The Prophet said, “I am only a human being, and you people have disputes. May be someone amongst you can present his case in a more eloquent and convincing manner than the other, and I give my judgment in his favor according to what I hear. Beware! If ever I give (by error) somebody something of his brother’s right then he should not take it as I have only, given him a piece of Fire.” (See Hadith No. 638. Vol. 3)