Sahih al-Bukhari 1963
Sahih al-Bukhari · Book 30: Fasting · To observe Saum (fast) continuously
'Narrated Abu Sa`id:
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ يُوسُفَ ، حَدَّثَنَا اللَّيْثُ ، حَدَّثَنِي ابْنُ الْهَادِ ، عَنْ عَبْدِ اللَّهِ بْنِ خَبَّابٍ ، عَنْ أَبِي سَعِيدٍ ـ رضى الله عنه ـ أَنَّهُ سَمِعَ النَّبِيَّ صلى الله عليه وسلم يَقُولُ " لاَ تُوَاصِلُوا، فَأَيُّكُمْ إِذَا أَرَادَ أَنْ يُوَاصِلَ فَلْيُوَاصِلْ حَتَّى السَّحَرِ " . قَالُوا فَإِنَّكَ تُوَاصِلُ يَا رَسُولَ اللَّهِ. قَالَ " إِنِّي لَسْتُ كَهَيْئَتِكُمْ، إِنِّي أَبِيتُ لِي مُطْعِمٌ يُطْعِمُنِي وَسَاقٍ يَسْقِينِ ".
That he had heard the Prophet (ﷺ) saying, "Do not fast continuously (practice Al-Wisal), and if you intend to lengthen your fast, then carry it on only till the Suhur (before the following dawn)." The people said to him, "But you practice (Al-Wisal), O Allah's Messenger (ﷺ)!" He replied, "I am not similar to you, for during my sleep I have One Who makes me eat and drink."