Musnad Ahmad 1153:2095

Sulayman ibn Dawud narrated to us, he said: Shu'bah informed us, from Yazid ibn Khumayr, he said: I heard 'Abdullah ibn Abi Musa—Ahmad said: And it is actually 'Abdullah ibn Abi Qays, and that is the correct [name], a freed slave of Banu Nasr ibn Mu'awiyah—he said: 'Aishah said to me: "Do not abandon the night prayer, for the Messenger of Allah (peace and blessings of Allah be upon him) used to never abandon it. And if he was ill or lazy, he would pray sitting."