The Messenger of Allah ﷺ heard a dispute at the door of his chamber, so he went out to them and said, "I am only a human being, and disputants come to me. One of you may be more eloquent than the other, so I assume he is truthful and rule in his favor. Whoever I rule in his favor with something that belongs to a Muslim by right, it is only a piece of the Fire, so let him take it or leave it."
أن رسول الله ﷺ سمع خصومة بباب حجرته، فخرج إليهم فقال: إنما أنا بشر، وإنه يأتيني الخصم، فلعل بعضكم أن يكون أبلغ من بعض، فأحسب أنه صادق فأقضي له بذلك، فمن قضيت له بحق مسلم، فإنما هي قطعة من النار، فليأخذها أو ليتركها.
Bukhari narrated it in Ahkam (7181), and Muslim in Aqdiyah (5:1713), both through Ibn Shihab Zuhri, who said, Urwa bin Zubayr informed me, that Zaynab bint Abu Salama informed him, that Umm Salama, the wife of the Prophet ﷺ, informed her, and she mentioned it.