Musannaf Ibn Abi Shaybah

Hazrat Sulaiman bin Yasar says that the case of Qasamah is true, because the Noble Prophet (peace and blessings be upon him) gave a verdict about it. We were with the Ansar in the presence of the Messenger of Allah (peace and blessings be upon him) when one of the Ansar went out, and suddenly they saw their companion lying in blood, writhing! So they returned to the Messenger of Allah (peace and blessings be upon him) and said, "The Jews have killed our man," and they mentioned the name of one of the Jews, but they had no witnesses. So the Messenger of Allah (peace and blessings be upon him) said to them, "If two witnesses other than yourselves testify, I will hand him over to you." But they had no witnesses. Then the Messenger of Allah (peace and blessings be upon him) said, "Take fifty oaths, and I will hand him over to you." The Ansar said, "We dislike taking an oath on something we have not seen." The Noble Prophet (peace and blessings be upon him) wanted to take fifty oaths from the Jews, but the Ansar said, "O Messenger of Allah (peace and blessings be upon him)! Indeed, the Jews do not care about oaths. How can we accept their oaths? Then they will kill our other people as well." So the Messenger of Allah (peace and blessings be upon him) paid the blood money for the murdered man from his own side.