Musnad Ahmad 1017:87

Ahmad ibn Abd al-Malik narrated to us, Sharik narrated to us, from Abu Ishaq and Abu Rabi‘ah al-Iyadi, from Abdullah ibn Buraydah, from his father, that the Messenger of Allah (peace and blessings of Allah be upon him) said to Ali: "O Ali, do not follow a glance with a glance, for you have the first [one], and you do not have the other."