Silsilat al-Ahadith al-Sahihah

Sayyiduna Abu Hurairah (may Allah be pleased with him) narrates that we were with the Messenger of Allah (peace and blessings of Allah be upon him), people began to pass by in front of him and he started asking: "Abu Hurairah! Who is this?" I would say, "This is such-and-such a man." He would say, "He is a righteous servant of Allah." Then someone else would pass by and he would ask, "Abu Hurairah! Who is this?" I would say, "This is such-and-such a man." He would say, "He is a bad man." Until Sayyiduna Khalid bin Walid (may Allah be pleased with him) passed by. I said, "O Messenger of Allah! This is Khalid bin Walid." The Messenger of Allah (peace and blessings of Allah be upon him) said, "Khalid is the best servant of Allah, he is one of the swords of Allah."

Abdul Malik bin Umair says that Sayyiduna Umar bin Khattab (may Allah be pleased with him) sent Sayyiduna Abu Ubaidah bin Jarrah (may Allah be pleased with him) as the governor of Syria and dismissed Sayyiduna Khalid bin Walid (may Allah be pleased with him). Sayyiduna Khalid said: The trustworthy one of this Ummah has been sent to you as your leader. I heard the Noble Prophet (peace and blessings of Allah be upon him) say: "The trustworthy one of this Ummah is Abu Ubaidah bin Jarrah." Sayyiduna Abu Ubaidah said: I heard the Messenger of Allah (peace and blessings of Allah be upon him) say: "Khalid is one of the swords of Allah, and he is the best young man of his tribe."