Musnad Abu Ya'la al-Mawsili 7:15

Ibrahim ibn al-Hajjaj al-Sami and Mu'alla ibn Mahdi narrated to us, they said: Abu 'Awanah narrated to us, from 'Umar ibn Abi Salamah, from his father, he said: The judge of the people of Palestine narrated to me, he said: I heard 'Abd al-Rahman ibn 'Awf saying: The Messenger of Allah (may Allah bless him and grant him peace) said: "Three things, by the One in Whose hand is the soul of Muhammad, I would certainly swear upon them: Wealth does not decrease from charity, so give charity. And no man pardons an injustice, seeking by it the Face of Allah, except that Allah raises him in honor by it on the Day of Resurrection. And no man opens for himself a door of begging, except that Allah opens for him a door of poverty."