The Chapters on Manumission (of Slaves)
19/6. Chapter:
Whoever Frees A Slave But Stipulates That He Should Serve Him
Sunan Ibn Majah
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ مُعَاوِيَةَ الْجُمَحِيُّ، حَدَّثَنَا حَمَّادُ بْنُ سَلَمَةَ، عَنْ سَعِيدِ بْنِ جُمْهَانَ، عَنْ سَفِينَةَ أَبِي عَبْدِ الرَّحْمَنِ، قَالَ أَعْتَقَتْنِي أُمُّ سَلَمَةَ وَاشْتَرَطَتْ عَلَىَّ أَنْ أَخْدُمَ النَّبِيَّ صلى الله عليه وسلم مَا عَاشَ .
It was narrated from that Safinah - Abu 'Abdur-Rahman-said : “Umm Salamah freed me but stipulated that I should serve the Prophet (ﷺ) as long he lived.”
Reference : Sunan Ibn Majah 2526In-book reference : Book 19, Hadith 15English translation : Vol. 3, Book 19, Hadith 2526