It was narrated that Anas bin Malik said:
"What the Messenger of Allah (ﷺ) most enjoined when he was dying and breathing his last was: The prayer; and those whom your right hands possess." (DE)
English reference (DE): Vol. 3, Book 22, Hadith 2697 (DE)
Arabic reference (DE): Book 22, Hadith 2801 (DE)