I came to the Messenger of Allah ﷺ and said, "Messenger of Allah, command me to fast."He said, "Fast one day, and you will have the reward of nine."I said, "Messenger of Allah, I have the strength for more, so increase it for me."He said, "Fast two days, and you will have the reward of eight days."I said, "Messenger of Allah, I have the strength for more, so increase it for me."He said, "Then fast three days, and you will have the reward of seven days."He kept reducing it for me until he said, "The best fast is the fast of my brother Dawud," or "the Prophet of Allah Dawud," Jareeri was uncertain which, "fast one day and break your fast the next."When Abdullah grew weak in his old age, he said, "If only I had been content with what the Prophet ﷺ commanded me."
حدثنا عبد الوهاب بن عطاء أخبرني الجريري عن أبي العلاء عن مطرف بن عبد الله
أتيت رسول الله ﷺ فقلت يا رسول الله مرني بصيام قال صم يوما ولك أجر تسعة قال قلت يا رسول الله إني أجد قوة فزدني قال صم يومين ولك أجر ثمانية أيام قال قلت يا رسول الله إني أجد قوة فزدني قال فصم ثلاثة أيام ولك أجر سبعة أيام قال فما زال يحط لي حتى قال إن أفضل الصوم صوم أخي داود أو نبي الله داود شك الجريري صم يوما وأفطر يوما فقال عبد الله لما ضعف ليتني كنت قنعت بما أمرني به النبي ﷺ
Its isnad is sahih. Jareeri is with damma on the jim, fatha on the ra, and sukun on the ya, a designation relating to Jareer, in the diminutive form, bin Abbad bin Dubaya bin Qays bin Thalaba bin Ukaba. His name was Saeed bin Iyas. His reliability was already established at 1312, and we add here that Bukhari gave his biography in Kabir 2/1/417-418.Abu Ala is Yazid bin Abdullah bin Shikhir, brother of Mutarrif. He narrates here from his brother, and this hadith is, in meaning, an abridgment of the one before it. See 6477 and 6545.Nasai narrated it in abridged form through this same route, but he added a man to the isnad. He related it at 1:325-326 through Mutamir bin Sulayman, from his father, who said, Abu Ala told us, from Mutarrif, from Ibn Abu Rabia, from Abdullah bin Amr, and he related it.This Ibn Abu Rabia, whom he added to the isnad, is not known to the scholars. In Tahdheeb 12:294 it is suggested that he might be the one mentioned just before him, meaning Harith bin Abdullah bin Abu Rabia al-Makhzumi. I consider it more likely that this narration contains an error, made either by Nasai or by one of the shaykhs in the chain, one of whom slipped and added an unknown man to the isnad.This hadith is a fragment of the story of Abdullah bin Amr and his zealous devotion to worship. Abu Ala Yazid bin Abdullah heard it, or heard part of it, as has already appeared in some of its narrations at 6535 and 6775, and here he narrates part of it from his elder brother, Mutarrif bin Abdullah. Mutarrif was among the senior early Successors, born during the lifetime of the Prophet. See his biography in Tahdheeb 10:173-174, Kabir by Bukhari 4/1/396-397, Tabaqat Ibn Saad 7/1/103-106, and Isabah 6:158.Indeed, it is not unlikely that he heard this from another man, who in turn heard it from Ibn Amr, but had that been the case, it would have been known and narrated through a clear and distinct route. As for relying on such an unknown figure, this possibility cannot be accepted.