Hadith 206:2
He said: Abu Nu'aym narrated to us, Sufyan narrated to us, from 'Ata', from Harb ibn 'Ubayd Allah al-Thaqafi, from his maternal uncle, who said: I came to the Prophet, peace and blessings of Allah be upon him, and he mentioned some things to him, and he asked him, saying: "Should I take a tithe (ushr) from them?" He said: "The tithes are only upon the Jews and the Christians, and there are no tithes upon the people of Islam."
قال: حدثنا أبو نعيم، حدثنا سفيان، عن عطاء، عن حرب بن عبيد الله الثقفي، عن خاله، قال: أتيت النبي صلى الله عليه وسلم فذكر له أشياء فسأله، فقال: أعشرها؟ فقال: " إنما العشور على اليهود، والنصارى، وليس على أهل الإسلام عشور "