It was narrated that Umm Salamah said:
‘By the One Who took his soul (i.e., the soul of the Prophet (ﷺ)), he did not die until he offered most of his prayers sitting down. And the dearest of the actions to him was the righteous action that the person does regularly, even if it were a little.”
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا أَبُو الأَحْوَصِ، عَنْ أَبِي إِسْحَاقَ، عَنْ أَبِي سَلَمَةَ، عَنْ أُمِّ سَلَمَةَ، قَالَتْ وَالَّذِي ذَهَبَ بِنَفْسِهِ ـ صلى الله عليه وسلم ـ مَا مَاتَ حَتَّى كَانَ أَكْثَرُ صَلاَتِهِ وَهُوَ جَالِسٌ وَكَانَ أَحَبُّ الأَعْمَالِ إِلَيْهِ الْعَمَلَ الصَّالِحَ الَّذِي يَدُومُ عَلَيْهِ الْعَبْدُ وَإِنْ كَانَ يَسِيرًا ‏.‏
GradeSahih (Darussalam)
English reference : Vol. 1, Book 5, Hadith 1225
Arabic reference : Book 5, Hadith 1283