"By the One in Whose Hand is my soul. The Messenger of Allah ﷺ did not pass away until most of his prayers were offered sitting down, except for the obligatory prayers, and the dearest of actions to him were those which were done persistently, even if they were few."  

وَالَّذِي نَفْسِي بِيَدِهِ مَا مَاتَ رَسُولُ اللَّهِ ﷺ حَتَّى كَانَ أَكْثَرُ صَلاَتِهِ قَاعِدًا إِلاَّ الْمَكْتُوبَةَ وَكَانَ أَحَبُّ الْعَمَلِ إِلَيْهِ مَا دَاوَمَ عَلَيْهِ وَإِنْ قَلَّ خَالَفَهُ عُثْمَانُ بْنُ أَبِي سُلَيْمَانَ فَرَوَاهُ عَنْ أَبِي سَلَمَةَ عَنْ عَائِشَةَ  

"The Messenger of Allah ﷺ did not refrain from (kissing) my forehead when he was fasting, and he did not die until most of his prayers were offered sitting down." Then she said something to the effect that (referred to the prayers) other than the obligatory prayers. "And the dearest of actions to him was that in which a person persists, even if it is little." (Using translation from Nasāʾī 1652)   

«مَا كَانَ رَسُولُ اللهِ ﷺ يَمْتَنِعُ مِنْ وَجْهِي وَهُوَ صَائِمٌ وَمَا مَاتَ حَتَّى كَانَ أَكْثَرُ صَلَاتِهِ قَاعِدًا ثُمَّ ذَكَرَ كَلِمَةً مَعَنَاهَا إِلَّا الْمَكْتُوبَةَ وَكَانَ أَحَبُّ الْعَمَلِ إِلَيْهِ مَا دَاوَمَ عَلَيْهِ الْإِنْسَانُ وَإِنْ كَانَ يَسِيرًا» خَالَفَهُ يُونُسُ