Musnad Abu Ya'la al-Mawsili 117:104

Ubayd Allah ibn Umar narrated to us, Ja'far ibn Sulayman narrated to us, Thabit narrated to us, from Anas, who said: When the day arrived on which the Messenger of Allah (may Allah bless him and grant him peace) entered Medina, everything in it became illuminated. And when the day arrived on which the Messenger of Allah (may Allah bless him and grant him peace) died, everything in it became darkened. He said: And we had not yet dusted our hands from the soil of the grave of the Messenger of Allah (may Allah bless him and grant him peace) before we felt a change in our hearts.