Bukhari 2896

Bukhari narrated from Sulayman bin Harb, from Muhammad bin Talha, from his father, from Musab, that Saad thought he had some merit, so the Prophet, peace and blessings be upon him, said...This is mursal.

Al-Hafiz said in Fath al-Bari, "Moreover, the apparent form of this account is disconnected (mursal), because Musab did not live in the time of this statement. However, it is to be understood that he heard it from his father. Indeed, it has been explicitly stated that Musab narrated it from his father, as recorded by Ismaili, who reported it via Muaz bin Hani, who said, Muhammad bin Talha narrated to us, and in it he said, from Musab bin Saad, from his father, who said, the Messenger of Allah, peace and blessings be upon him and his family, said, then he mentioned the marfu portion without what came at its beginning. Nasai likewise reported it via Masaar, from Talha bin Musarrif, from Musab, from his father, with the wording that he thought he had some superiority over those beneath him." The hadith continues.