The Messenger of Allah ﷺ did not die until most of his prayers were performed sitting, except for the obligatory ones. The deeds most beloved to him were those a servant maintained consistently, even if they were small.
ما مات رسول الله ﷺ حتى كان أكثر صلاته قاعدا إلا المكتوبة، وكان أحب العمل إليه ما داوم عليه العبد وإن كان يسيرا.
Nasai (1654) and Imam Ahmad (26709) both narrated it through the hadith of Shuba, from Abu Ishaq, who said, I heard Abu Salama, from Umm Salama, and he mentioned it. Abu Ahwas followed him in Ibn Majah (1225), and Sufyan followed him in Imam Ahmad (26709) and Nasai, both from Abu Ishaq with the same wording, except that Abu Ahwas did not mention the exception "except the obligatory prayer," which is an addition from reliable narrators. Abu Ishaq was a mudallis, but he stated clearly that he heard it directly in the narration of Nasai, and Ibn Hibban graded it sahih (2507), narrating it from this route with an explicit statement of hearing. Shuba and Sufyan were among those who narrated from Abu Ishaq before his memory became confused, and Abu Ahwas followed them.This hadith has also been narrated through the route of Abu Ishaq, from Aswad, from Ayesha, who said, "The Messenger of Allah ﷺ did not die until most of his prayer was performed sitting, except the obligatory prayer, and the deed most beloved to him was that which a person maintained consistently, even if it was small." It has been said that this is not preserved. It was narrated from Abu Ishaq by his son Yunus, who was among those who heard from his father after his memory became confused. Imam Ahmad narrated it (24819) from Abu Naeem, from Yunus, and Nasai narrated it (1654) through another route from Yunus, but he placed it within the musnad of Umm Salama. The sahih version is from the hadith of Ayesha, which will come in the chapter on what is commanded regarding moderation in prayer and maintaining it consistently, even if it is little.