Musnad Ahmad 32:232

Isma'il narrated to us, Ayyub informed us, from Humayd ibn Hilal, from Anas ibn Malik, who said: The Messenger of Allah (peace and blessings of Allah be upon him) delivered a sermon and said: "Zayd took the banner and was struck down, then Ja'far took it and was struck down, then Abdullah ibn Rawahah took it and was struck down, then Khalid took it without being appointed, and Allah granted him victory." And he said: "It does not please them"—or he said: "It does not please me"—"that they are with us." He said: And his eyes were shedding tears.