Hubayrah bin Yarim said: Sayyiduna al-Hasan (may Allah be pleased with him) gave an address and said: "Yesterday a man departed from you whom those before did not surpass in knowledge, and whom those after will not attain. The Messenger of Allah (peace and blessings be upon him) would send him on a mission and give him the banner, with Jibril on his right and Mika'il on his left, and he would not return until Allah, the Mighty and Majestic, granted him victory."
Hadith Referenceالمعجم الكبير للطبراني / باب الحاء / 2711