It is narrated from Sayyidah Umm Salamah (may Allah be pleased with her) that she said: "He (peace and blessings be upon him) did not pass away until most of his prayer was performed sitting, and the deed most pleasing to him (peace and blessings be upon him) was the one that its doer keeps up constantly, even if it is little", meaning the Prophet (peace and blessings be upon him).
Hadith Referenceالمعجم الكبير للطبراني / مسند النساء / 19819