Umm Salamah reported: By the One who took the Prophet’s soul, peace and blessings be upon him, he did not die until he prayed most of his prayers sitting down. The most beloved deeds to him were righteous deeds that a servant performs regularly, even if they are easy.
Source: Sunan Ibn Mājah 4237
Grade: Sahih (authentic) according to Al-Albani
عَنْ أُمِّ سَلَمَةَ قَالَتْ وَالَّذِي ذَهَبَ بِنَفْسِهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ مَا مَاتَ حَتَّى كَانَ أَكْثَرُ صَلَاتِهِ وَهُوَ جَالِسٌ وَكَانَ أَحَبَّ الْأَعْمَالِ إِلَيْهِ الْعَمَلُ الصَّالِحُ الَّذِي يَدُومُ عَلَيْهِ الْعَبْدُ وَإِنْ كَانَ يَسِيرًا
4237 سنن ابن ماجه كتاب الزهد باب المداومة على العمل
3434 المحدث الألباني خلاصة حكم المحدث صحيح في صحيح ابن ماجه