Full Sharh — Sahih al-Bukhari 1141
حَدَّثَنَا عَبْدُ الْعَزِيزِ بْنُ عَبْدِ اللَّهِ، قَالَ حَدَّثَنِي مُحَمَّدُ بْنُ جَعْفَرٍ، عَنْ حُمَيْدٍ، أَنَّهُ سَمِعَ أَنَسًا ـ رضى الله عنه ـ يَقُولُ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم يُفْطِرُ مِنَ الشَّهْرِ حَتَّى نَظُنَّ أَنْ لاَ يَصُومَ مِنْهُ، وَيَصُومُ حَتَّى نَظُنَّ أَنْ لاَ يُفْطِرَ مِنْهُ شَيْئًا، وَكَانَ لاَ تَشَاءُ أَنْ تَرَاهُ مِنَ اللَّيْلِ مُصَلِّيًا إِلاَّ رَأَيْتَهُ وَلاَ نَائِمًا إِلاَّ رَأَيْتَهُ. تَابَعَهُ سُلَيْمَانُ وَأَبُو خَالِدٍ الأَحْمَرُ عَنْ حُمَيْدٍ.
English Translation
Narrated Anas bin Malik:Sometimes Allah's Messenger (ﷺ) would not fast (for so many days) that we thought that he would not fast that month and he sometimes used to fast (for so many days) that we thought he would not leave fasting throughout that month and (as regards his prayer and sleep at night), if you wanted to see him praying at night, you could see him praying and if you wanted to see him sleeping, you could see him sleeping
Source
Sahih al-Bukhari(صحيح البخاري)
Prayer at Night (Tahajjud)
Hadith Number
1141