أَخْبَرَنَا مُحَمَّدُ بْنُ إِسْمَاعِيلَ بْنِ إِبْرَاهِيمَ، قَالَ حَدَّثَنَا يَزِيدُ، قَالَ حَدَّثَنَا حَمَّادٌ، ح وَأَخْبَرَنِي زَكَرِيَّا بْنُ يَحْيَى، قَالَ حَدَّثَنَا عَبْدُ الأَعْلَى، قَالَ حَدَّثَنَا حَمَّادٌ، عَنْ ثَابِتٍ، عَنْ شُعَيْبِ بْنِ عَبْدِ اللَّهِ بْنِ عَمْرٍو، عَنْ أَبِيهِ، قَالَ قَالَ لِي رَسُولُ اللَّهِ صلى الله عليه وسلم " صُمْ يَوْمًا وَلَكَ أَجْرُ عَشْرَةٍ " . فَقُلْتُ زِدْنِي . فَقَالَ " صُمْ يَوْمَيْنِ وَلَكَ أَجْرُ تِسْعَةٍ " . قُلْتُ زِدْنِي . قَالَ " صُمْ ثَلاَثَةَ أَيَّامٍ وَلَكَ أَجْرُ ثَمَانِيَةٍ " . قَالَ ثَابِتٌ فَذَكَرْتُ ذَلِكَ لِمُطَرِّفٍ فَقَالَ مَا أُرَاهُ إِلاَّ يَزْدَادُ فِي الْعَمَلِ وَيَنْقُصُ مِنَ الأَجْرِ وَاللَّفْظُ لِمُحَمَّدٍ .
It was narrated from Shuaib bin 'Abdullah bin 'Amr that his father said: "The Messenger of Allah said to me: 'Fast one day and you will have the reward of ten.' I said: 'Let me fast more.' He said: 'Fast two days and you will have the reward of nine.' I said: 'Let me fast more than that.' He said: 'Fast three days and you will have the reward of eight." (One of the narrators) Thabit said: "I mentioned that to Mutarrif and he said: 'I only see that he is making more effort for less reward.'" Translation Not Available
Book Ref: Sunan An Nisai Book 22 Hadith 2396
Web Ref: Sunan An Nisai Vol 3 Book 22 Hadith 2398