Hadith on Ramadan: The Prophet did not pray some nights in the mosque so that it would not become an obligation

Aisha reported: The Messenger of Allah, peace be upon him, prayed one night in the mosque and some people prayed along with him. Then, he prayed the following night and many people joined him. Then, on the third or fourth night there was a large gathering but the Messenger of Allah did not come out for them. When it was morning, he said, “I saw what you were doing, but I refrained from coming to you because I fear that this prayer might become an obligation for you.” Aisha said, “This was during the month of Ramadan.”

[Sahih Muslim, Book 4, Number 1666]

عَنْ عَائِشَةَ  أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ صَلَّى فِي الْمَسْجِدِ ذَاتَ لَيْلَةٍ فَصَلَّى بِصَلَاتِهِ نَاسٌ ثُمَّ صَلَّى مِنْ الْقَابِلَةِ فَكَثُرَ النَّاسُ ثُمَّ اجْتَمَعُوا مِنْ اللَّيْلَةِ الثَّالِثَةِ أَوْ الرَّابِعَةِ فَلَمْ يَخْرُجْ إِلَيْهِمْ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فَلَمَّا أَصْبَحَ قَالَ قَدْ رَأَيْتُ الَّذِي صَنَعْتُمْ فَلَمْ يَمْنَعْنِي مِنْ الْخُرُوجِ إِلَيْكُمْ إِلَّا أَنِّي خَشِيتُ أَنْ تُفْرَضَ عَلَيْكُمْ قَالَ وَذَلِكَ فِي رَمَضَانَ

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