He heard him say that the Messenger of Allah ﷺ said, "Whoever claims descent from someone other than his father, or attributes his loyalty to someone other than his rightful patrons, upon him is the curse of Allah, the angels, and all of humanity."
حدثنا عفان حدثنا وهيب حدثنا عبد الله بن عثمان بن خثيم عن سعيد بن جبير
أنه سمعه يقول إن رسول الله ﷺ قال من ادعى إلى غير أبيه أو تولى غير مواليه فعليه لعنة الله والملائكة والناس أجمعين
Its isnad is sahih. Ibn Majah (2:68) narrated it through Muhammad bin Abu Dayf from Abdullah bin Uthman bin Khuthaym. His commentator quoted from the author of Zawaid that its isnad contains Ibn Abu Dayf, and said, "I have not seen anyone comment on him, either negatively or with affirmation of reliability, while the rest of the narrators in the isnad meet the standard of Muslim." This Ibn Abu Dayf was not alone in narrating this hadith, for Ahmad narrated it here, as you can see, from Affan, from Wahib, from Ibn Khuthaym, and this isnad is sahih as clear as the sun. See 1915 and 1924, and also see 1297 and 1553.