Sunan Ibn Majah 1191

Abu Bakr bin Abu Shaibah narrated to us: Muhammad bin Bishr narrated to us: Said bin Abu Arubah narrated to us, from Qatadah, from Zurarah bin Awfa, from Sad bin Hisham, who said: I asked Aishah: Mother of the Believers, tell me about the Witr prayer of the Messenger of Allah (ﷺ). She said: We would prepare his toothstick and water for purification. Allah would cause him to rise during the night at whatever time He willed. He would use the toothstick and perform ablution, then pray nine rakahs, sitting only at the eighth. There he would supplicate to his Lord, remember Allah, praise Him, and call upon Him. Then he would rise without giving the taslim, stand, and pray the ninth rakah. Then he would sit, remember Allah, praise Him, supplicate to his Lord, and send blessings upon His Prophet. Then he would give a taslim that we could hear. After giving the taslim, he would pray two rakahs while seated. That made eleven rakahs. When the Messenger of Allah (ﷺ) grew older and gained weight, he prayed Witr as seven rakahs, then prayed two rakahs after giving the taslim.