The final instructions of the Messenger of Allah ﷺ as death approached and he was at his last breath were, "The prayer, and those whom your right hands possess."
حدثنا أحمد بن المقدام حدثنا المعتمر بن سليمان سمعت أبي يحدث عن قتادة
كانت عامة وصية رسول الله ﷺ حين حضرته الوفاة وهو يغرغر بنفسه الصلاة وما ملكت أيمانكم
Sourcing, its chain is daif. Ahmad (30/117) narrated it from the hadith of Sulayman Taymi through him, and Ibn Hibban graded it sahih (Mawarid), no. 1220, and Busiri graded it hasan. Abu Yaala (5/347), no. 2990, narrated it from Ahmad bin Miqdam through him, and Hurayam bin Abdul-Ala Abu Hamza Asadi followed him in narrating it there (p. 309, no. 2933) from Mutamir through him.Qatada narrated it with "an" phrasing, as mentioned earlier, no. 175, and for his hadith there are corroborating reports, all of which are daif. See no. 1625 and the following hadith, and others. Allah knows best.