Biography of Tha'labah ibn al-Harith
Dhahabi: Tha'labah b. al-Harith b. Haraam b. Ka'b b. Ghunm b. Ka'b b. Salama fought at Badr with the Prophet ﷺ and was killed at Taif as a martyr, as stated by Ibn Mandah.
Abu Nai'm mentioned Tha'labah b. al-Jadh' in his biography, and also mentioned that Musa b. Uqba, from Ibn Shahab, mentioned that Tha'labah was one of the Khazraj who fought at Badr, then from Banu Salama, then from Banu Haraam.
He said: Some later narrators mentioned him, meaning Ibn Mandah, who said: Tha'labah b. al-Harith b. Haraam b. Ka'b b. Ghunm b. Ka'b b. Salama fought at Badr and was killed as a martyr at Taif. He dedicated a separate biography for him, and they are one and the same.
I said: Abu Nai'm's statement is correct, and Ibn Mandah made a mistake. Al-Jadh' was a nickname for Tha'labah. He mentioned it in the biography of Thabit b. al-Jadh', saying: Al-Jadh' is Tha'labah b. Zayd b. al-Harith b. Haraam. Despite this, how can he say here Tha'labah b. al-Harith, when he omitted the name of his father Zayd? He is Tha'labah b. Zayd b. al-Harith b. Haraam, as stated in his biography of his father, and many others, including Hisham and Ibn Habib, mentioned this lineage.