Musnad Ahmad 25:627

Al-Hasan ibn Yahya and al-Taliqani narrated to us, they said: al-Fadl ibn Musa narrated to us, Abdullah ibn Sa’id ibn Abi Hind narrated to us, from Thawr ibn Zayd, from Ikrimah, from Ibn Abbas, who said: "The Prophet, peace and blessings of Allah be upon him, used to pray while turning to the right and the left, without twisting his neck behind his back." Al-Taliqani said: Thawr narrated to me, from Ikrimah, who said: The Messenger of Allah, peace and blessings of Allah be upon him, used to... [the same as above].