The Messenger of Allah ﷺ used to fast for so many days in succession that it would be said he never broke his fast, and he would refrain from fasting for so many days that he would scarcely fast at all, except for two days of the week. If they fell within his fasting period, well and good, otherwise he would still fast them. He did not fast in any month as much as he fasted in Shaban.I said, "Messenger of Allah, you fast until it seems you will never break your fast, and you abstain from fasting until it seems you will hardly fast at all, except for two days, which you fast whether they fall within your fasting period or not."He asked, "Which two days?"I said, "Monday and Thursday."He said, "Those are two days on which deeds are presented to the Lord of the Worlds, and I love for my deeds to be presented while I am fasting."I said, "I have not seen you fast in any month as much as you fast in Shaban."He said, "That is a month which people overlook, between Rajab and Ramadan. It is a month in which deeds are raised up to the Lord of the Worlds, and I love for my deeds to be raised up while I am fasting."
كان رسول الله ﷺ يصوم الأيام يسرد حتى يقال: لا يفطر، ويفطر الأيام حتى لا يكاد أن يصوم إلا يومين من الجمعة، إن كان في صيامه، وإلا صامهما، ولم يكن يصوم من شهر من الشهور ما يصوم من شعبان، فقلت: يا رسول الله، إنك تصوم لا تكاد أن تفطر، وتفطر حتى لا تكاد أن تصوم إلا يومين إن دخلا في صيامك وإلا صمتهما! قال: أي يومين؟ قال: قلت: يوم الاثنين ويوم الخميس. قال: ذانك يومان تعرض فيهما الأعمال على رب العالمين، وأحب أن يعرض عملي وأنا صائم. قال: قلت: ولم أرك تصوم من شهر من الشهور ما تصوم من شعبان! قال: ذاك شهر يغفل الناس عنه بين رجب ورمضان، وهو شهر ترفع فيه الأعمال إلى رب العالمين، فأحب أن يرفع عملي وأنا صائم.
Imam Ahmad narrated it (21753) from Abdul-Rahman bin Mahdi, who said, "Thabit bin Qays Abu Ghusn narrated to us, Abu Saeed Maqburi narrated to me, Usama bin Zayd narrated to me," and he related it. Nasai narrated it (2357) through the route of Abdul-Rahman bin Mahdi, in abbreviated form. Its chain is hasan because of Thabit bin Qays Abu Ghusn Madani, whom Imam Ahmad and others considered trustworthy, while Abu Dawud and others considered him daif, except that his hadith is hasan. Munziri also graded it hasan through the route of Nasai in Mukhtasar Sunan Abu Dawud.It has another route narrated by Abu Dawud (2436) and Imam Ahmad (21744), both through the route of Aban, who said, "Yahya bin Abu Kathir narrated to me, Umar bin Abu Hakam bin Thawban narrated to me, from the freed slave of Qudama bin Mazun, from the freed slave of Usama bin Zayd, that he went with Usama to Wadi Qura seeking some wealth of his own. Usama used to fast on Monday and Thursday, so his freed slave said to him, "Why do you fast on Monday and Thursday when you are such an old man?" He said, "The Prophet of Allah ﷺ used to fast on Monday and Thursday, and when he was asked about that, he said, 'The deeds of the servants are presented on Monday and Thursday.'"Abu Dawud said, "This is what Hisham Dastawai said, from Yahya, from Umar bin Abu Hakam."I say, its chain is daif, for the freed slave of Qudama bin Mazun and the freed slave of Usama bin Zayd are both unknown, except that the second one's name is Harmala, and some have treated him leniently, saying, "He is truthful."Munziri said, "In its chain there are two unknown men." Then he mentioned the hadith of Nasai through the route of Abu Saeed Kaysan Maqburi, and said, "This is a hasan hadith." So Munziri graded the first route as hasan, while the second route, which is the route of Abu Dawud, he graded as daif, but by combining the two routes the hadith becomes hasan.It has another route as well, which is what Ibn Khuzayma narrated (2119) through the route of Shurahbil bin Saad, from Usama, who said, "The Messenger of Allah ﷺ used to fast on Monday and Thursday and would say, 'On these two days, deeds are presented.'"Shurahbil bin Saad is Abu Saad Madani, the freed slave of the Ansar. Nasai considered him daif, while Ibn Hibban considered him trustworthy, and he is acceptable as a corroborating narrator. In Taqrib it says, "He was truthful, but he became confused toward the end of his life," yet this narration was not affected by that confusion, since there are corroborating narrations for it.