Musannaf Ibn Abi Shaybah 34254 — The virtues of Ali bin Abi Talib

It is narrated from Sayyiduna Ali (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said to Sayyiduna Ali (may Allah be pleased with him): "O Ali, you have a treasure in Paradise, and you are the one with its two horns (its two ends). When your glance falls on someone, do not follow it with a second glance, for one glance is forgiven, but the second is not forgiven."