Al-Walīd ibn Muslim related: Wahshī ibn Ḥarb narrated to us, from his father, from his grandfather Wahshī, that when Abū Bakr appointed Khālid to fight the apostates he said, “I heard the Messenger of Allah ﷺ say, ‘Khālid ibn al-Walīd is one of Allah’s swords; Allah has unsheathed it against the disbelievers and the hypocrites.’” This report is recorded by Aḥmad in his Musnad (1).

Hishām ibn ʿUrwah, from his father, said: “Some people of Banū Sulaym lapsed into apostasy, so Abū Bakr sent Khālid ibn al-Walīd against them. He gathered a group of their men in pens and then burned them. ʿUmar said to Abū Bakr, ‘Will you leave a man who punishes with the punishment of Allah?’ He replied, ‘By Allah, I will never sheath (2) a sword that Allah has drawn against His enemy.’ He then ordered him on, and Khālid marched toward Musaylimah (3).”

Ḍamrah ibn Rabīʿah reported: al-Saybānī (4) informed me, from Abū al-ʿAjmāʾ—indeed he is Abū al-ʿAjfāʾ—al-Sulamī, who said: It was said to ʿUmar, “O Commander of the Believers, if only you would appoint a successor!” He replied, “Had I found Abū ʿUbaydah and then given him the leadership, and later come before my Lord and He asked me, ‘Why did you choose him?’ I would say, ‘I heard Your servant and close friend say: For every nation there is a guardian, and the guardian of this nation is Abū ʿUbaydah.’ And had I found Khālid ibn al-Walīd and then installed him, and afterwards stood before my Lord, I would say: ‘I heard Your servant and close friend say: Khālid is one of Allah’s swords; Allah has drawn it…’”