Muwatta Malik, Book 6, Hadith 247 (In-Book) ⓘ

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.

حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، عَنِ ابْنِ شِهَابٍ، عَنْ عُرْوَةَ بْنِ الزُّبَيْرِ، عَنْ عَائِشَةَ، زَوْجِ النَّبِيِّ صلى الله عليه وسلم أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم صَلَّى فِي الْمَسْجِدِ ذَاتَ لَيْلَةٍ فَصَلَّى بِصَلاَتِهِ نَاسٌ ثُمَّ صَلَّى اللَّيْلَةَ الْقَابِلَةَ فَكَثُرَ النَّاسُ ثُمَّ اجْتَمَعُوا مِنَ اللَّيْلَةِ الثَّالِثَةِ أَوِ الرَّابِعَةِ فَلَمْ يَخْرُجْ إِلَيْهِمْ رَسُولُ اللَّهِ صلى الله عليه وسلم فَلَمَّا أَصْبَحَ قَالَ ‏ "‏ قَدْ رَأَيْتُ الَّذِي صَنَعْتُمْ وَلَمْ يَمْنَعْنِي مِنَ الْخُرُوجِ إِلَيْكُمْ إِلاَّ أَنِّي خَشِيتُ أَنْ تُفْرَضَ عَلَيْكُمْ ‏" ‏ ‏.‏ وَذَلِكَ فِي رَمَضَانَ ‏.‏