The expedition led by Ghalib ibn ʿAbd Allah al-Laythi:

Al-Waqidi said: Aflah ibn Saʿid related to me from Bashir ibn Muhammad—the son of the Companion who was shown the call to prayer, ʿAbd Allah ibn Zayd—who said: With Ghalib ibn ʿAbd Allah were Abu Masʿud ʿUqbah ibn ʿAmr al-Ansari, Kaʿb ibn ʿUjrah, and ʿAlbah ibn Zayd.

When Ghalib drew near the enemy he sent out scouts; they returned with their report. He then advanced and, once he was within sight of them by night—after they had milked their animals and settled down—he rose, praised Allah, extolled Him, and commanded obedience. He said, “When I pronounce the takbīr, pronounce it with me, and draw your swords.” He then gave the rest of the account of how they encircled the camp, adding, “We struck with our swords wherever we wished among them, shouting our battle-cry, ‘Kill! Kill!’ Usamah charged at a man who cried, ‘There is no god but Allah,’” and he went on with the story.

Yunus ibn Bukayr, on the authority of Muhammad ibn Ishaq, said: A shaykh from the tribe of Aslam told me—quoting men of his people—that the Messenger of Allah ﷺ dispatched Ghalib ibn ʿAbd Allah al-Kalbi, of the Layth branch, to the territory of the Banu Murrah. There he met Mirdas ibn Nahik, an ally of theirs from the Harqah, and Usamah killed him.

Muhammad ibn Usamah ibn Muhammad ibn Usamah narrated to me, from his father, from his grandfather Usamah ibn Zayd, who said: “I, together with a man from the Ansar, caught up with him—meaning Mirdas. When we raised our swords over him he declared, ‘I bear witness that there is no god but Allah,’ but we did not desist until we had killed him.

“When we returned to the Messenger of Allah ﷺ and informed him of what had happened, he said, ‘Usamah! Who will answer for “There is no god but Allah”?’ I replied, ‘O Messenger of Allah, he only said it to protect himself from being killed.’ He said, ‘Then who will answer for “There is no god but Allah”?’

“By Him who sent him with the truth, he kept repeating it to me until I wished that none of my previous Islam had existed and that I had embraced Islam only on that day and had not killed him.”