Musnad Abu Ya'la al-Mawsili 150:290

Al-Mu'alla ibn Mahdi narrated to us, Abu 'Awanah narrated to us, from Abu Ishaq, from al-Aswad, who said: I asked 'Aisha about the prayer of the Prophet (may Allah bless him and grant him peace) at night. She said: "He used to sleep during the first part of the night and stand during the last part of it, so he would pray what was decreed for him. When he finished his prayer, he would incline toward his bed. If he had a need for his wife, he would come to his wife, then sleep in his state without touching water. When he heard the first call (adhan) or the caller, he would stand. If he was in a state of major ritual impurity (junub), he would perform ghusl, and if he was not in a state of major ritual impurity, he would perform his wudu for prayer, then pray two rak'ahs, then go out to the mosque."