Sayyidah Umm Salamah (may Allah be pleased with her) said that the Prophet (peace and blessings be upon him) heard the voices of people disputing at his door. He (peace and blessings be upon him) went out to them and said: "I am a human being, and you bring your disputes to me. Perhaps some are more eloquent, and I may judge in his favour thinking him truthful. So whoever I judge in favour of (with a Muslim's right), it is a piece of Hellfire, whether he takes it or leaves it."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب آداب القاضي / 20503