Hilal bin Amir narrates from his father, who said: I saw the Prophet (peace and blessings be upon him) at Mina delivering a sermon while riding a mule, and he (peace and blessings be upon him) was wearing a red cloak, and Sayyiduna Ali (may Allah be pleased with him) was in front of him, relaying his (peace and blessings be upon him) words (to the people).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجمعة / 5983