Al-Ashtar (may Allah have mercy on him) said: Sayyiduna Khalid bin al-Walid (may Allah be pleased with him) began telling us on his own without our asking, and said: "The Messenger of Allah (peace and blessings be upon him) sent me to one of the tribes of the Arabs." Then he narrated a hadith similar to it.
Hadith Referenceالمعجم الكبير للطبراني / باب الخاء / 3818