Musnad Abu Ya'la al-Mawsili 150:115

Bishr ibn al-Walid narrated to us, Sharik narrated to us, from Yahya ibn Sa'id, from al-Qasim ibn Muhammad, from Aisha, who said: The Prophet, may Allah bless him and grant him peace, got up from his bed during a part of the night. I thought he wanted to go to one of his wives, so I followed him until he stood at the graves. He said: "Peace be upon you, abode of a believing people, and we shall, by Allah, join you." Then he said: "O Allah, do not deprive us of their reward, and do not try us after them." She said: Then he turned and saw me, and he perceived me. He said: "Woe to her, if she were able, she would not have done [this]."