Musannaf Ibn Abi Shaybah

Hazrat Iyas bin Salamah (may Allah have mercy on him) narrates that my father informed me that indeed the Messenger of Allah (peace and blessings be upon him) sent him to call Hazrat Ali (may Allah be pleased with him). And he said: "I will surely give the flag to such a man who loves Allah and His Messenger (peace and blessings be upon him), and Allah and His Messenger (peace and blessings be upon him) love him." The narrator says: So I brought him while I was walking ahead to show him the way because he was suffering from an eye ailment. Then the Messenger of Allah (peace and blessings be upon him) applied his blessed saliva to his eyes, then granted him the flag. And on that very day, Allah granted victory at his hands.