Full Sharh — Mishkat al-Masabih 1984
وَعَنْ أَنَسٍ قَالَ: دَخَلَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ عَلَى أُمِّ سُلَيْمٍ فَأَتَتْهُ بِتَمْرٍ وَسَمْنٍ فَقَالَ: «أَعِيدُوا سَمْنَكُمْ فِي سِقَائِهِ وَتَمْرَكُمْ فِي وِعَائِهِ فَإِنِّي صَائِمٌ» . ثُمَّ قَامَ إِلَى نَاحِيَةٍ مِنَ الْبَيْتِ فَصَلَّى غَيْرَ الْمَكْتُوبَةِ فَدَعَا لأم سليم وَأهل بَيتهَا. رَوَاهُ البُخَارِيّ
English Translation
Anas said that the Prophet visited Umm Sulaim, and when she brought him some dates and clarified butter he said, “Put your butter back in its container and your dates in their vessel, for I am fasting.” He then went to a separate part of the house and prayed a prayer which was not one of the prescribed prayers, and invoked a blessing on Umm Sulaim and the inhabitants of her house. Bukhari transmitted it.
Source
Mishkat al-Masabih(مشكاة المصابيح)
Fasting
Hadith Number
1984