Narrated 'Abd Allah b. 'Amr:

The Messenger of Allah ﷺ 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.

حَدَّثَنَا سُلَيْمَانُ بْنُ حَرْبٍ، أَخْبَرَنَا حَمَّادٌ، عَنْ عَطَاءِ بْنِ السَّائِبِ، عَنْ أَبِيهِ، عَنْ عَبْدِ اللَّهِ بْنِ عَمْرٍو، قَالَ قَالَ لِي رَسُولُ اللَّهِ ﷺ " 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 .