Sahih al-Bukhari 924
Narrated Aisha:
Once in the middle of the night Allah's Messenger (ﷺ) (p.b.u.h) went out and prayed in the mosque and some 
men prayed with him. The next morning the people spoke about it and so more people gathered and 
prayed with him (in the second night). They circulated the news in the morning, and so, on the third 
night the number of people increased greatly. Allah's Messenger (ﷺ) (p.b.u.h) came out and they prayed 
behind him. On the fourth night the mosque was overwhelmed by the people till it could not 
accommodate them. Allah's Messenger (ﷺ) came out only for the Fajr prayer and when he finished the 
prayer, he faced the people and recited "Tashah-hud" (I testify that none has the right to be 
worshipped but Allah and that Muhammad is His Apostle), and then said, "Amma ba'du. Verily your 
presence (in the mosque at night) was not hidden from me, but I was afraid that this prayer (Prayer of 
Tahajjud) might be made compulsory and you might not be able to carry it out."
حَدَّثَنَا يَحْيَى بْنُ بُكَيْرٍ، قَالَ حَدَّثَنَا اللَّيْثُ، عَنْ عُقَيْلٍ، عَنِ ابْنِ شِهَابٍ، قَالَ أَخْبَرَنِي عُرْوَةُ، أَنَّ عَائِشَةَ، أَخْبَرَتْهُ أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم خَرَجَ ذَاتَ لَيْلَةٍ مِنْ جَوْفِ اللَّيْلِ، فَصَلَّى فِي الْمَسْجِدِ، فَصَلَّى رِجَالٌ بِصَلاَتِهِ فَأَصْبَحَ النَّاسُ فَتَحَدَّثُوا، فَاجْتَمَعَ أَكْثَرُ مِنْهُمْ فَصَلَّوْا مَعَهُ، فَأَصْبَحَ النَّاسُ فَتَحَدَّثُوا فَكَثُرَ أَهْلُ الْمَسْجِدِ مِنَ اللَّيْلَةِ الثَّالِثَةِ، فَخَرَجَ رَسُولُ اللَّهِ صلى الله عليه وسلم فَصَلَّوْا بِصَلاَتِهِ، فَلَمَّا كَانَتِ اللَّيْلَةُ الرَّابِعَةُ عَجَزَ الْمَسْجِدُ عَنْ أَهْلِهِ حَتَّى خَرَجَ لِصَلاَةِ الصُّبْحِ، فَلَمَّا قَضَى الْفَجْرَ أَقْبَلَ عَلَى النَّاسِ، فَتَشَهَّدَ ثُمَّ قَالَ ‏
"‏ أَمَّا بَعْدُ فَإِنَّهُ لَمْ يَخْفَ عَلَىَّ مَكَانُكُمْ، لَكِنِّي خَشِيتُ أَنْ تُفْرَضَ عَلَيْكُمْ فَتَعْجِزُوا عَنْهَا ‏"‏‏.‏ تَابَعَهُ يُونُسُ‏.‏