Hadith 10:270
Umm Salama told that the Prophet was saying during his illness, “Maintain the prayer and care for your slaves.” Baihaqi transmitted it in Shu'ab al-iman , and Ahmad and Abu Dawud transmitted something similar on the authority of ‘Ali.
وَعَنْ أُمِّ سَلَمَةَ عَنِ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ أَنَّهُ كَانَ يَقُولُ فِي مَرَضِهِ: «الصَّلَاةَ وَمَا مَلَكَتْ أَيْمَانُكُمْ» . رَوَاهُ الْبَيْهَقِيُّ فِي شعب الْإِيمَان وَرَوَى أَحْمَدُ وَأَبُو دَاوُدَ عَنْ عَلِيٍّ نَحْوَهُ
Original Reference: Mishkat al-Masabih 3356, 3357