That the Prophet ﷺ said: "When the penalty (of blood money) goes to a Mukatab, or an inheritance, then he inherits in accordance with as much as he is freed from it." And the Prophet ﷺ said: "The Mukatab is given the blood-money of a free person in accordance to what he has paid (for his freedom), and that of a slave in accordance to what remains." [He said:] There is something on this from Umm Salamah.  

عَنِ النَّبِيِّ ﷺ قَالَ إِذَا أَصَابَ الْمُكَاتَبُ حَدًّا أَوْ مِيرَاثًا وَرِثَ بِحِسَابِ مَا عَتَقَ مِنْهُ وَقَالَ النَّبِيُّ ﷺ يُؤَدِّي الْمُكَاتَبُ بِحِصَّةِ مَا أَدَّى دِيَةَ حُرٍّ وَمَا بَقِيَ دِيَةَ عَبْدٍ قَالَ وَفِي الْبَابِ عَنْ أُمِّ سَلَمَةَ  

From his father, from his grandfather that he heard the Messenger of Allah ﷺ delivering a Khutbah in which he said: "Whoever gives a writ of emancipation to his slave, for one hundred Uqiyyah, and he pays it to him less then ten Uqiyah." - or he said: "Ten Dirham" - "then he becomes incapable (of paying the remainder), the he remains a slave."  

سَمِعْتُ رَسُولَ اللَّهِ ﷺ يَخْطُبُ يَقُولُ مَنْ كَاتَبَ عَبْدَهُ عَلَى مِائَةِ أُوقِيَّةٍ فَأَدَّاهَا إِلاَّ عَشْرَ أَوَاقٍ أَوْ قَالَ عَشَرَةَ دَرَاهِمَ ثُمَّ عَجَزَ فَهُوَ رَقِيقٌ  

That the Messenger of Allah ﷺ said: "When one of you (women) has a Mukatab ho has with him what will fulfill (the Kitabah) then observe Hijab from him."  

قَالَ رَسُولُ اللَّهِ ﷺ إِذَا كَانَ عِنْدَ مُكَاتَبِ إِحْدَاكُنَّ مَا يُؤَدِّي فَلْتَحْتَجِبْ مِنْهُ