Sayyiduna Wathilah bin al-Asqa' (may Allah be pleased with him) says that the Messenger of Allah (peace and blessings be upon him) came out to us and said: "You think that I will be the last of you to die, whereas I am the first of you to die; then you will follow me in group after group, striking one another's necks."
Hadith Referenceالمعجم الكبير للطبراني / باب الواو / 18387