Musnad Ahmad 1156:254

'Affan narrated to us, Abu al-Ahwas narrated to us, he said: Abu Ishaq narrated to us, from Abu Salamah bin 'Abd al-Rahman bin 'Awf, from Umm Salamah, the Mother of the Believers, who said: "By the One in Whose hand is his soul, he did not die until most of his prayer was while he was sitting. And the most beloved of deeds to him was the righteous deed which the servant persists in, even if it were little."