It is narrated from Sayyiduna Wahshi bin Harb (may Allah be pleased with him) that Sayyiduna Abu Bakr al-Siddiq (may Allah be pleased with him) sent Sayyiduna Khalid bin al-Walid (may Allah be pleased with him) to fight the people of apostasy. He was spoken to about it (that Khalid should be recalled), but he refused to recall him and said: I heard the Messenger of Allah (peace and blessings be upon him), mentioning Khalid bin al-Walid, say: "What an excellent servant of Allah, a brother of the tribe, and one of the swords of Allah."
Hadith Referenceالمعجم الكبير للطبراني / باب الخاء / 3783