The Messenger of Allah ﷺ said, "The greatest in slander among people are three: a man who, having a poetic feud with another, lampoons an entire tribe because of him, a man who disowns his father, and one who accuses his mother of adultery."
حدثنا أبو بكر بن أبي شيبة حدثنا عبيد الله عن شيبان عن الأعمش عن عمرو بن مرة عن يوسف بن ماهك عن عبيد بن عمير
قال رسول الله ﷺ إن أعظم الناس فرية لرجل هاجى رجلا فهجا القبيلة بأسرها ورجل انتفى من أبيه وزنى أمه
[Hasan] Bayhaqi reported it, 10/241, from the hadith of Shayban with this chain. Ibn Hibban graded it sahih, no. 2014, as did Busiri, and Hafiz graded it hasan in Fath al-Bari, 10/539. It has a corroborating witness in Bukhari, no. 3509, and elsewhere, covering part of it, and it is supported by the Quran, "And let not the hatred of a people prevent you from being just" [Maidah 5:8].