Musannaf Ibn Abi Shaybah

Hazrat Abdul Malik bin Umair (may Allah have mercy on him) narrates that Hazrat Umar (may Allah be pleased with him) appointed Hazrat Abu Ubaidah (may Allah be pleased with him) as the leader over the people of Shaam and removed Hazrat Khalid bin Waleed (may Allah be pleased with him) from his position. Upon this, Hazrat Khalid bin Waleed (may Allah have mercy on him) said: "You have been sent as the leader over the people by appointing the trustworthy person of this Ummah." Hazrat Abu Ubaidah (may Allah be pleased with him) said: "I heard the Messenger of Allah (peace and blessings be upon him) say that Khalid is one of the swords of Allah. And he is the best young man of the tribe."