Musnad Ahmad 907:71

Muhammad ibn Ja'far narrated to us, Shu'bah narrated to us, from Sulayman, who said: I heard al-Musayyab ibn Rafi' narrating from Tamim ibn Tarafah, from Jabir ibn Samurah, from the Prophet, peace and blessings of Allah be upon him, that he said: "Does one of you not fear, when he raises his sight while he is in prayer, that his sight will not return to him?"