Musnad Ahmad 32:518

'Abd al-Samad narrated to us, Shu'bah narrated to us, and Abu Dawud said: Shu'bah informed us of the meaning, Thabit narrated to us, he said: I heard Anas saying to a woman of his family: "Do you know such-and-such woman?" For the Messenger of Allah (peace and blessings of Allah be upon him) passed by her while she was weeping over a grave, and he said to her: "Fear Allah and be patient." She said to him: "Leave me alone, for you are not afflicted with my calamity." He said: And she did not recognize him. It was said to her: "It is the Messenger of Allah (peace and blessings of Allah be upon him)." So she was seized by something like death, and she came to his door, and she did not find a doorkeeper at it. She said: "O Messenger of Allah, I did not recognize you." He said: "Verily, patience is at the first shock."