Sufyan reported it as a marfu hadith, while Masaar reported it as mawquf. He said, "Among the major sins is that a man curses his own parents."They asked, "How can a man curse his own parents?"He replied, "He insults another man's father, so that man insults his father in return, and he insults another man's mother, so that man insults his mother in return."
حدثنا وكيع حدثنا مسعر وسفيان عن سعد بن إبراهيم عن حميد بن عبد الرحمن بن عوف
رفعه سفيان ووقفه مسعر قال من الكبائر أن يشتم الرجل والديه قالوا وكيف يشتم الرجل والديه قال يسب أبا الرجل فيسب أباه ويسب أمه فيسب أمه
Its chain of transmission is sahih. Saad bin Ibrahim bin Abdul-Rahman bin Awf is a trustworthy Successor, well known, with many hadiths to his credit. Many of his narrations have already been cited, and reference to him has already been made at 709 and 1480. Bukhari gave his biography in al-Kabir 2/2/52-53. Here he narrates from his uncle Humayd bin Abdul-Rahman bin Awf.Muslim related this hadith in 1:37 through the route of Ibn Hadi, and through the route of Shubah, and through the route of Thawri, all three of them from Saad bin Ibrahim. Tirmidhi related it in 117 through the route of Ibn Hadi from Saad. Abu Dawud related it in 5141 (4:500 of Awn al-Mabud) through the route of Ibrahim bin Saad from his father Saad bin Ibrahim, with this same chain, as a raised hadith.So these four, Ibn Hadi, Shubah, Thawri, and Ibrahim bin Saad, all related it from Saad bin Ibrahim as a raised hadith. It therefore does no harm that Masaar related it as a stopped hadith, for the raising of the hadith is an addition from a trustworthy narrator, indeed from trustworthy narrators, and a raised hadith is not faulted on account of a stopped one.Ibn Kathir mentioned it in the tafsir, 2:420, by way of Bukhari's narration, then mentioned that Muslim related it and that Tirmidhi graded it sahih, and in Umdat al-Tafsir 3:153 and 5:108 of Anaam. See also 2817, 2915-2917.