Musnad Ahmad 483:3

'Abd al-Razzaq narrated to us, Ibn Jurayj informed us, Ziyad—meaning Ibn Sa'd—narrated to me, from Yazid ibn Yazid ibn Jabir, from Makhul, from Zayd ibn Jariyah al-Tamimi, who said: Habib ibn Maslamah narrated to me, saying: "I witnessed the Messenger of Allah, peace and blessings of Allah be upon him, granting a third as a *nafl* (extra share of spoils)."