Musnad Ahmad 958:5

Abdullah narrated to us, Muhammad ibn Ja’far al-Warkani narrated to me, Sharik narrated to us, from Simak, from Qabisah ibn Hulb, from his father, from the Prophet, may Allah bless him and grant him peace, that he said: I asked him about the food of the Christians, and he said: "Let not food in which you have imitated the Christians cause any doubt, or let it not prick, in your chest." And he said: "And he used to turn away from his left and from his right, and he would place one of his hands upon the other."