Musannaf Ibn Abi Shayba 18:1085

Abu Bakr narrated to us, he said: Abu Khalid narrated to us, from Hajjaj, from Amr ibn Shu’ayb, from his father, from his grandfather, that Huwayyisah and Muhayyisah, the sons of Mas’ud, and Abdullah and Abd al-Rahman, the sons of so-and-so, went out to trade in Khaybar. Then an assault was made upon Abdullah, and he was killed. He said: They mentioned that to the Prophet, may Allah bless him and grant him peace. The Prophet, may Allah bless him and grant him peace, said: "You take fifty oaths and thereby establish your claim." They said: "O Messenger of Allah, how can we take oaths when we did not witness it?" He said: "Then the Jews will absolve you," meaning they will take the oaths. He said: They said: "O Messenger of Allah, then the Jews will kill us." He said: So the Messenger of Allah, may Allah bless him and grant him peace, paid his blood money from his own [resources]. And he said: Yahya ibn Sa’id informed me, from Ibn Yasar, from the Prophet, may Allah bless him and grant him peace, the like of this, except that he said: Abd al-Rahman, the brother of the slain, went to speak, and the Prophet, may Allah bless him and grant him peace, said: "The elder, the elder." So the elder spoke. Then the Messenger of Allah, may Allah bless him and grant him peace, said: "You take fifty oaths and thereby establish your claim, or they take fifty oaths for you." He said: They said: "O Messenger of Allah, how can we accept the oaths of a disbelieving people?" He said: So the Prophet, may Allah bless him and grant him peace, paid his blood money from his own [resources].