Mukhtasar Bukhari (Abridged) 1123 — Sin of one who knowingly argues

Umm al-Mu'mineen Umm Salamah (may Allah be pleased with her) narrates from the Noble Prophet (peace and blessings be upon him) that he (peace be upon him) heard the sound of a dispute at the door of his chamber, so he (peace be upon him) came out (the case was presented). Then he (peace be upon him) said: "I am also a human being (I do not know the unseen). People who have disputes come to me for judgment, so perhaps one of you is more eloquent in presenting his case than the other, so I think that he has spoken the truth, and I give a decision in his favor because of this. So if I (unknowingly) give someone the right of another Muslim, then (he should understand that) it is a piece of Hellfire; now he may take it or leave it."