Muwatta Malik #1592
The Mukatab
The Arabic includes the chain of narration (sanad) and the collector's commentary; the English translation shows the Prophet's words only.
حَدَّثَنِي مَالِكٌ، عَنْ نَافِعٍ، أَنَّ عَبْدَ اللَّهِ بْنَ عُمَرَ، كَانَ يَقُولُ الْمُكَاتَبُ عَبْدٌ مَا بَقِيَ عَلَيْهِ مِنْ كِتَابَتِهِ شَىْءٌ .
Malik related to me from Nafi that Abdullah ibn Umar said, "A
mukatab is a slave as long as any of his kitaba remains to be paid."
About Muwatta Malik
This hadith is #1592 from Muwatta Malik, in the Book of The Mukatab.