Musnad Ahmad 5:799

Yahya ibn Ishaq narrated to us, Hammad ibn Salamah narrated to us, from Muhammad ibn Ishaq, from Muhammad ibn Ibrahim, from Salamah ibn Abi al-Tufayl, from Ali, may Allah be pleased with him, who said: The Messenger of Allah, peace and blessings of Allah be upon him, said to me: "Do not let a glance follow a glance, for the first one is for you, but the last one is not for you."