She said, "I wanted to fast two days consecutively, but Bashir stopped me, saying that the Messenger of Allah ﷺ had forbidden it. He said, 'That is what the Christians do.'"Affan's version reads, "That is what the Christians do. Fast instead as Allah has commanded you, 'then complete the fast until night' [Baqarah 2:187]. So when night comes, break your fast."
قالت أردت أن أصوم يومين مواصلة، فمنعني بشير، وقال: إن رسول الله ﷺ نهي عنه. وقال: يفعل ذلك النصارى- وقال عفان: يفعل ذلك النصارى، ولكن صوموا كما أمركم الله: {ثم أتموا الصيام إلى اليل}. فإذا كان الليل فأفطروا.
Imam Ahmad (21955), Abu Dawud Tayalisi (1221), Tabarani in Al-Kabeer (31/2), and Abd bin Humayd (429) all narrated it, all of them from the hadith of Ubaydullah bin Iyad bin Laqeet Sadusi, from his father, from Laila the wife of Bashir, and he mentioned it. Its chain is sahih. Ubaydullah and his father are both trustworthy, and although Hafiz said of Ubaydullah, "truthful," Nasai, Ajli, Abu Naeem and others declared him trustworthy.Laila, the wife of Bashir, was from Banu Shayban, and she narrated two or three hadiths from the Prophet ﷺ, as stated by Abu Umar. Ibn Hibban mentioned her among the Companions, saying, "It is said that she had companionship with the Prophet." Then he mentioned her among the trustworthy Followers. Her name was Juhzuma, but the Prophet ﷺ changed it to Laila.Tirmidhi recorded in Shamail (46) from Iyad bin Laqeet, from Juhzuma the wife of Bashir bin Khasasiya, who said, "I saw the Messenger of Allah ﷺ coming out of his house shaking his head." Ibn Hajar mentioned all of this in Isabah, in the biography entry of Juhzuma. As for Haythami in Majma (158/3), he did not find anyone who mentioned Laila, and he said, "The rest of its narrators are the narrators of Sahih." I say, this is because the biographers wrote her entry under the name Juhzuma, not under the name Laila.On this topic there is also what was narrated from Jabir bin Abdullah, who said, "The Prophet ﷺ used to fast continuously from one predawn hour to the next." Tabarani narrated it in Awsat (3768) from Ali bin Abdul-Aziz, who said, Abu Ghassan Malik bin Ismail Nahdi narrated to us, who said, Sharik bin Abdullah narrated to us, from Muhammad bin Aqeel, from Jabir bin Abdullah, and he mentioned it. In it is Sharik bin Abdullah, who is Nakhai, known for making many errors.Likewise, it is not sahih as a marfu narration from Jabir, "There is no continuous fasting during the fast." Abu Dawud Tayalisi narrated it (1873) from Kharija bin Musab, from Haram bin Uthman, from Abu Atiq, from Jabir bin Abdullah, and he mentioned it. In it are Kharija bin Musab and his teacher Haram bin Uthman, both of whom are extremely daif. He also narrated it (1874) from Yaman Abu Huzaifa, from Abu Abs, from Jabir, similarly. Yaman Abu Huzaifa is daif by consensus, and Abu Abs is unknown.On this topic there is also what was narrated from Ali bin Abu Talib, who said, "The Messenger of Allah ﷺ used to fast continuously until the predawn hour." Ahmad (700), Tabarani in Al-Kabeer (67/1), Ibn Abu Shayba (3/82–83), and Abd bin Humayd (85) all narrated it, all of them through the route of Israel, from Abdul-Ala, from Muhammad bin Ali, from Ali bin Abu Talib, and he mentioned it. Muhammad bin Ali is the son of Ali bin Abu Talib, known as Ibn Hanafiya, whose kunya is Abu Qasim, and it is also said, Abu Abdul-Rahman, as mentioned in Muntakhab Abd bin Humayd. Its chain is daif because of Abdul-Ala, who is Ibn Amir Thalabi, whom the majority of scholars have graded daif. As for Haythami, he said in Majma (158/3), "Its narrators are the narrators of Sahih," but this is a mistake on his part, for Thalabi is only among the narrators of the Sunan.These hadiths taken together have been used as evidence that continuous fasting is one of the distinguishing characteristics of the Prophet ﷺ, and that it is forbidden for anyone else, due to the reason the Prophet ﷺ explained, which is that Allah truly feeds him and gives him drink, and this is one of his distinguishing characteristics that no one else shares with him. Scholars have other interpretations, but what I have mentioned is the closest of them to being correct.