Musnad Ahmad 9:30

Al-Fadl ibn Dukayn narrated to us, Isra'il narrated to us, from Ibrahim ibn Muhajir, he said: Someone who heard 'Amr ibn Hurayth narrated to me, narrating from Sa'id ibn Zayd, he said: I heard the Messenger of Allah, peace and blessings of Allah be upon him, saying: "O assembly of the Arabs, praise Allah who has lifted the tithes (al-'ushur) from you."