She was asked whether the Messenger of Allah ﷺ used to combine multiple surahs in a single rakah. She replied, "From the Mufassal."
أنها سئلت: هل كان رسول الله ﷺ يجمع بين السور في ركعة؟ قالت: المفصل.
Ahmad (25687) and Ishaq bin Rahwayh (1301) both narrated it from Waki, who said, Kahmas bin Hasan told us, from Abdullah bin Shaqiq, that he asked Ayesha, and he related the hadith. Its chain of transmission is sahih, and Ibn Khuzayma (539) also graded it sahih, narrating it through the route of Salm bin Junada, from Waki, in the same way.The disagreement occurred only regarding Kahmas bin Hasan. Waki narrated from him as mentioned above, while Yazid bin Harun narrated from him with an addition, a question about the Messenger of Allah ﷺ praying while sitting, to which Ayesha replied, "He used to pray sitting after the people had exhausted him." Abu Dawud (956) narrated this from Uthman bin Abu Shayba, who said, Yazid bin Harun told us, in the same manner.Uthman bin Umar also narrated it from Kahmas, adding a third matter, the Duha prayer, to which Ayesha said, "He used to perform the Duha prayer when he returned from being away." Ibn Khuzayma (539) narrated this from Yaqub bin Ibrahim Dawraqi, from Uthman bin Umar, from Kahmas, relating the hadith.Khalid bin Harith also narrated it from Kahmas, mentioning the Duha prayer and the question about fasting an entire month, to which she said, "I never knew him to fast a whole month except Ramadan, nor did he break his fast until he had fasted part of it, until he passed away." He did not mention in it the recitation of multiple surahs in a single rakat, nor performing the prayer while sitting. Nasai (2184) narrated this from Ismail bin Masud, who said, Khalid, that is, Ibn Harith, informed us, and he related the hadith.Ubaydullah bin Muaz narrated it from his father, from Kahmas, mentioning only the Duha prayer. Muslim (717) narrated it through this route. Ahmad (25385) narrated it from Muhammad bin Jafar, Yazid bin Harun, and Abu Abdul-Rahman Muqri, and Ishaq bin Rahwayh (1300) narrated it from Nadr bin Shumayl, all of them from Kahmas, and they combined in it all four matters, namely, the Duha prayer, performing the prayer while sitting, joining surahs together, and fasting Ramadan.All these chains of transmission are sahih, and the matter comes down to brevity and elaboration, which is something well known in the transmission of hadith. Praise be to Allah, Lord of the worlds.