Musannaf Ibn Abi Shayba 5:469

Ibn Abi Za’idah narrated to us, from Shu’bah, from al-Hakam, from ‘Abdullah ibn Nafi’, from his father—and he was a slave owned by Banu Hashim—that he asked ‘Umar: "Should one give charity?" He said: "With a dirham and a loaf of bread."