Musnad Ahmad 27:970

'Affan narrated to us, Abu 'Awanah narrated to us, Simak bin Harb narrated to us, from Mus'ab bin Sa'd, who said: 'Abdullah bin 'Umar entered upon 'Abdullah bin 'Amir to visit him, and he [Ibn 'Amir] said: "Why do you not supplicate for me?" He [Ibn 'Umar] said: "For I heard the Messenger of Allah (ﷺ) say: 'Indeed, Allah, the Mighty and Majestic, does not accept a prayer without purification, nor charity from spoils of war taken before distribution (ghulul).'" And he [Ibn 'Amir] had been over Basra, meaning as a governor.