Musnad Ahmad 30:3266

Muhammad ibn Ja‘far narrated to us, he said: ‘Awf narrated to us, from al-Hasan, he said: It reached me that the Messenger of Allah (may Allah bless him and grant him peace) said: "The Hour will not be established until you fight a people who wear shoes of hair, and until you fight a people with broad faces, flat noses, and small eyes, as if their faces are hammered shields."