Man Lā Yaḥḍuruh al-Faqīh

Hadith 70
slavery-captives
3490 - وَ رَوَى عُمَرُ صَاحِبُ اَلْكَرَابِيسِ عَنْ أَبِي عَبْدِ اَللَّهِ عَلَيْهِ اَلسَّلاَمُ : "فِي رَجُلٍ كَاتَبَ مَمْلُوكَهُ وَ اِشْتَرَطَ عَلَيْهِ أَنَّ مِيرَاثَهُ لَهُ فَرُفِعَ ذَلِكَ إِلَى عَلِيٍّ عَلَيْهِ اَلسَّلاَمُ فَأَبْطَلَ شَرْطَهُ وَ قَالَ "شَرْطُ اَللَّهِ قَبْلَ شَرْطِكَ" ".
Hadith.3490 - Umar, the companion of al-Karabis, narrated from Abu Abdullah (as), regarding a man who entered into a mukataba (a contract of emancipation) with his slave and stipulated that the slave's inheritance would belong to him (the master). This case was presented to Imam Ali ibn Abi Talib (as) , who invalidated the condition and said: "The condition of Allah (swt) precedes your condition."
Source: Shaykh Muḥammad b. ʿAlī al-Ṣaduq