Musnad Ahmad 930:1

Abu Sa'd Muhammad ibn Maysar al-Saghani narrated to us, Abu Ja'far al-Razi narrated to us, from al-Rabi' ibn Anas, from Abu al-'Aliyah, from Ubayy ibn Ka'b: That the polytheists said to the Prophet, may Allah bless him and grant him peace: "O Muhammad, attribute your Lord to us." So Allah, Blessed and Exalted is He, revealed: "Say, 'He is Allah, [who is] One, Allah, the Eternal Refuge.' [Al-Ikhlas: 1-2] He neither begets nor is born, nor is there to Him any equivalent."