Musnad Ahmad 30:3020

Yahya narrated to us, from Isma'il—meaning Ibn Abi Khalid—who said: Qays ibn Abi Hazim narrated to me, saying: We came to Abu Hurayrah to greet him. He said: We said: "Narrate to us." He said: "I accompanied the Messenger of Allah (peace and blessings of Allah be upon him) for three years. I was never more intelligent in any years than I was in them, nor was it more beloved to me to memorize what the Messenger of Allah (peace and blessings of Allah be upon him) said than in them. And I saw him gesturing with his hand: 'Close to the approach of the Hour, you will fight a people whose sandals are made of hair, and you will fight a people with small eyes and red faces, as if their faces are hammered shields.'"