Musnad Ahmad 290:0

Narrated to us by Yahya ibn Sa'id, from Muhammad ibn 'Amr, from Abu Salamah, from Al-'Abbas ibn Mirdas as-Sulami, who said: The Messenger of Allah (ﷺ) supplicated for his Ummah on the evening of Arafah, and he was answered: "I have forgiven them, except for the oppressors, for I will take retribution from the oppressor on behalf of the oppressed." He (the Prophet) said: "O Lord, if You willed, You could give the oppressed from Paradise and forgive the oppressor." He was not answered on that evening. Then, when it was the morning of Muzdalifah, he supplicated again, and he was answered. The Messenger of Allah (ﷺ) laughed or smiled. His companions said: "May my father and mother be sacrificed for you, O Messenger of Allah, you laughed at an hour you did not usually laugh at. What made you laugh?" He said: "I laughed because when the enemy of Allah, Iblis, heard that Allah had answered my supplication and forgiven my Ummah, he began to throw dust upon his head and cry out in woe and destruction. So his panic at what I heard made me laugh."