Sunan ibn Mājah Ḥadīth [4237]
It was narrated that Umm Salamah said: “By the One Who took his (peace and blessings of Allāh be upon him) soul, he did not die until most of his prayers were offered sitting down. And the most beloved of deeds to him was a righteous deed which a person persists in doing, even if it is something small.”
Commentary by Dārussalām added.