Musnad Ahmad 30:928

Abu Qatan and Isma'il ibn 'Umar narrated to us, they said: Yunus narrated to us, from Mujahid Abu al-Hajjaj, from Abu Hurayrah, who said: The Messenger of Allah, may Allah bless him and grant him peace, said: "Indeed, Allah, the Almighty and Majestic, boasts to the angels about the people of 'Arafat. He says: 'Look at My servants, disheveled and dusty.'"