Sunan An-Nasa'i

It was narrated from Sahi bin Abi Hathmah that:'Abdullah bin SAahi and Nubayysah bin Mas'ud bin Zaid went o Khaibar, and at that time there was peace treaty. They went their separate ways to about their business, then Muhayysah came upon 'Abdullah in Sahl lying dead in a pool of blood. He buried him, then he came to AL-Madinah. 'Abdur-Rahman bin Sahi. Huwayysah, and Muhayysah came to the Messenger of Allah, and 'Abdur-Rehman started to speak, but he was the youngest of them, so the Messenger of Allah said: ""Let the elders speak first."" So he fell silent and they (the other two) spoke. The Messenger of Allah said: ""Will you swear fifty oaths, then you will receive compensation or be entitled to retaliate?"" They said: ""O Messenger of Allah, how can we swear an oath when we did not witness, and did not see (what happened)?"" He said: ""The n can the Jews swear fifty oaths declaring their innocence?"" They said: ""O Messenger of Allah, how can we accept the oath of a disbelieving people?"" So the Messenger of Allah paid the blood money himself