Musnad Abu Ya'la al-Mawsili 109:91

Muhammad ibn ‘Amr ibn Jabalah narrated to us, Muhammad ibn Marwan narrated to us, from Hisham, from Abu al-Zubayr, from Jabir, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "There are no days better in the sight of Allah than the ten days of Dhu al-Hijjah." A man said: "O Messenger of Allah, are they better, or an equal number of days spent in Jihad in the way of Allah?" He said: "They are better than an equal number of days spent in Jihad in the way of Allah, except for one whose face is smeared in the dust." "And there is no day better in the sight of Allah than the day of ‘Arafah. Allah descends to the lowest heaven and boasts to the inhabitants of the heaven about the inhabitants of the earth. He says: 'Look at My servants, disheveled and dusty, having come from every deep mountain pass. They have not seen My mercy, and they have not seen My punishment.' And I have not seen a day in which more people are freed from the Fire than the day of ‘Arafah."