Musnad Abu Ya'la al-Mawsili 150:284

Harun ibn Ma'ruf narrated to us, Ibn Wahb narrated to us, Abdullah ibn Umar narrated to me, from Abu al-Nadr, from Abu Salamah, from Aisha, that the Messenger of Allah (ﷺ) went out one night of Ramadan to the mosque after the night prayer (Isha), and he prayed. People saw him and prayed with his prayer. When the second night came, he went out again, and the people saw him, so they gathered, said the takbir, and prayed with his prayer. When the third night came, the mosque was filled, but the Messenger of Allah (ﷺ) did not go out to them. They began as if they were signaling him to come out to them. He said, "O Aisha, what is the matter with the people?" I said, "O Messenger of Allah, they prayed with you these two nights, so they desired that you come out to them." Then he went out to them and said, "O people, take upon yourselves of deeds what you can bear, for Allah does not grow weary until you grow weary. And the most beloved of deeds to Allah is that which is continuous, even if it is small. You continued until I feared that it would be made obligatory upon you." Aisha said: The Messenger of Allah (ﷺ) used to pray eleven rak'ahs, standing, and two rak'ahs sitting. When he wanted to bow, he would stand and recite, then bow, then he would perform witr with one. Abu Salamah said: I said, "How was his prayer in the month of Ramadan?" She said, "He did not increase in the month of Ramadan upon this."