حَدَّثَنَا سُلَيْمَانُ بْنُ حَرْبٍ، أَخْبَرَنَا حَمَّادٌ، عَنْ عَطَاءِ بْنِ السَّائِبِ، عَنْ أَبِيهِ، عَنْ عَبْدِ اللَّهِ بْنِ عَمْرٍو، قَالَ قَالَ لِي رَسُولُ اللَّهِ صلى الله عليه وسلم ‏"‏ صُمْ مِنْ كُلِّ شَهْرٍ ثَلاَثَةَ أَيَّامٍ وَاقْرَإِ الْقُرْآنَ فِي شَهْرٍ ‏"‏ ‏.‏ فَنَاقَصَنِي وَنَاقَصْتُهُ فَقَالَ ‏"‏ صُمْ يَوْمًا وَأَفْطِرْ يَوْمًا ‏"‏ ‏.‏ قَالَ عَطَاءٌ وَاخْتَلَفْنَا عَنْ أَبِي فَقَالَ بَعْضُنَا سَبْعَةَ أَيَّامٍ وَقَالَ بَعْضُنَا خَمْسًا ‏.‏

Narrated 'Abd Allah b. 'Amr: The Messenger of Allah (PBUH) said to me: Keep fast for three days of month, and finish the recitation of the Qur'an in one month. I and he differed among ourselves on period of time. He said: Fast one day and give it up other day. The narrator 'Ata said: The people differed from my father (in narrating the period of time). Some narrated seven days and others five. Translation Not Available

Book Ref: Sunan Abi Dawud Book 6 Hadith 1389
Web Ref:  Sunan Abi Dawud Book 6 Hadith 1384