Muwatta Malik Book 6, Hadith 1
Yahya related to me from Malik from Ibn Shihab from Urwa ibn az-
Zubayr from A'isha, the wife of the Prophet, may Allah bless him and
grant him peace, that the Messenger of Allah, may Allah bless him and
grant him peace, prayed in the mosque one night and people prayed
behind him. Then he prayed the next night and there were more people.
Then they gathered on the third or fourth night and the Messenger of
Allah, may Allah bless him and grant him peace, did not come out to
them. In the morning, he said, "I saw what you were doing and the only
thing that prevented me from coming out to you was that I feared that
it would become obligatory (fard) for you." This happened in Ramadan.
Yahya related to me from Malik from Jafar ibn Muhammad from his father that the Messenger of Allah, may Allah bless him and grant him peace, gave two khutbas on the day of jumua and sat down between them.
Yahya related to me from Malik from Ibn Shihab from Abu Salama ibn Abd ar-Rahman ibn Awf from Abu Hurayra that the Messenger of Allah, may Allah bless him and grant him peace, used to exhort people to watch the night in prayer in Ramadan but never ordered it definitely. He used to say, "Whoever watches the night in prayer in Ramadan with trust and expectancy, will be forgiven all his previous wrong actions."
Ibn Shihab said, "The Messenger of Allah, may Allah bless him and grant him peace, died while that was still the custom, and it continued to be the custom in the caliphate of Abu Bakr and at the beginning of the caliphate of Umar ibn al-Khattab."