Musnad Abu Ya'la al-Mawsili 149:32

Mus'ab ibn 'Abd Allah narrated to us, Ibrahim ibn Sa'd narrated to us, from Muhammad ibn Ishaq, from Yahya ibn 'Abbad, from 'Aishah, who said: The Messenger of Allah (may Allah bless him and grant him peace) performed the night prayer (tahajjud) in his house, and 'Abbad ibn Bishr performed the night prayer in the mosque. The Messenger of Allah (may Allah bless him and grant him peace) heard his voice, so he said: "O 'Aishah, is this 'Abbad ibn Bishr?" I said: "Yes." He said: "O Allah, have mercy on 'Abbad."