Musnad Abu Ya'la al-Mawsili 249:8

Muhammad ibn Isma'il ibn Abi Samina al-Basri narrated to us, Muhammad ibn Kathir narrated to us, from al-Awza'i, from Rabi'ah, from Wathilah ibn al-Asqa' who said: The Messenger of Allah (may Allah bless him and grant him peace) came out to us and said: "You claim that I am the last of you in death? Nay, I am the first of you in death. And you will follow me in factions, some of you striking the necks of others."