Musnad Abu Ya'la al-Mawsili 150:374

Harun ibn Ma'ruf narrated to us, Ibn Wahb narrated to us, and Mu'awiyah ibn Salih narrated to us, Abu Hamzah narrated to me, from 'Aishah, the wife of the Prophet, may Allah bless him and grant him peace, who said: "I never saw the Messenger of Allah, may Allah bless him and grant him peace, sleeping before the 'Isha prayer, nor engaging in idle talk after it. Either he would be remembering [Allah] and thus gaining, or he would be sleeping and thus remaining safe."