On the authority of his grandfather Mujjāʿah: that he came to the Prophet ﷺ seeking the blood-wit for his brother—who had been killed by Banū Sadūs of Banī Dhuhl—and the Prophet ﷺ said: "If I were to assign a blood-wit to a polytheist, I would have assigned it to your brother, but I will give you compensation from it." So the Prophet ﷺ wrote for him a document granting one hundred camels from the first fifth (khums) that would come from the polytheists of Banī Dhuhl. He took a portion of it, and then Banū Dhuhl embraced Islam. Thereafter Mujjāʿah sought it from Abū Bakr, presenting him with the document of the Prophet ﷺ, so Abū Bakr wrote for him a grant of twelve thousand ṣāʿs from the charity (ṣadaqah) of al-Yamāmah: four thousand of wheat, four thousand of barley, and four thousand of dates. And in the document of the Prophet ﷺ for Mujjāʿah was written: "In the name of Allah, the Most Gracious, the Most Merciful. This is a document from Muḥammad the Prophet for Mujjāʿah ibn Murārah of Banī Salmā: I have given him one hundred camels from the first fifth that comes from the polytheists of Banī Dhuhl, as compensation for his brother."(1)

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(1) Its chain of transmission is weak due to the unknown status of Sirāj ibn Mujjāʿah and al-Dukhail ibn Iyās. Muḥammad ibn ʿĪsā: he is Ibn al-Ṭabbāʿ al-Baghdādī.
It was also narrated by Ibn Qāniʿ in "Muʿjam al-Ṣaḥābah" 3/112–113, and Ibn al-Athīr in "Usd al-Ghābah" 5/62 via the chain of ʿAnbasah ibn ʿAbd al-Wāḥid, with this same chain of transmission. It is found in al-Bukhārī's "al-Tārīkh al-Kabīr" 8/44 as a suspended (muʿallaq) narration.
Al-Khaṭṭābī said: The meaning of "al-ʿuqba" is compensation. It seems that he gave him this only as a conciliation for him, or for those of his people behind him, toward Islam.
And his saying: "And he was among the abdāl." It appears in "Musnad Aḥmad" (2275) the hadith of ʿUbādah ibn al-Ṣāmit, raised to the Prophet: "The abdāl in this nation are thirty, like Ibrāhīm, the friend of the Most Merciful. Whenever a man dies, Allah replaces him with another man." Its chain is weak. And the hadith of ʿAlī also in it (896), raised to the Prophet: "The abdāl will be in al-Shām, and they are forty men. Whenever a man dies, Allah replaces him with another man. Through them rain is sent, through them victory is granted over enemies, and punishment is diverted from the people of al-Shām through them." This also is not authentic, as is clarified in our annotations on the "Musnad."
And Mujjāʿah: al-Mundhirī said: It is with a ḍammah on the mīm, a shaddah and fatḥah on the jīm, and some lighten it, and after the alif there is an unpointed ʿayn and a tāʾ of feminization.