Musnad Abu Ya'la al-Mawsili 111:87

Musa narrated to us, Abd al-Rahman narrated to us, from Sufyan, from Abd al-Malik ibn Abi Bashir, from Abdullah ibn al-Musawir, who said: I heard Ibn Abbas say: The Messenger of Allah (peace and blessings of Allah be upon him) said: "The believer is not the one who eats his fill while his neighbor is hungry by his side."