To those also, to whom your right hand was pledged, give their due portion. A man made an agreement with another man (in early days of Islam), and there was no relationship between the ; one of them inherited from the other. The following verse of Surat Al-Anfal abrogated it: "But kindred by blood have prior right against each other."  

{ وَالَّذِينَ عَقَدَتْ أَيْمَانُكُمْ فَآتُوهُمْ نَصِيبَهُمْ } كَانَ الرَّجُلُ يُحَالِفُ الرَّجُلَ لَيْسَ بَيْنَهُمَا نَسَبٌ فَيَرِثُ أَحَدُهُمَا الآخَرَ فَنَسَخَ ذَلِكَ الأَنْفَالُ فَقَالَ تَعَالَى { وَأُولُو الأَرْحَامِ بَعْضُهُمْ أَوْلَى بِبَعْضٍ }  

[Machine] "The man used to make a pact with the man, although there was no relation between them for one to inherit the other. So Allah abolished this with the verse of Anfal: "And relatives are more entitled to inherit from one another in the Book of Allah." (Surah Al-Ahzab, verse 6). Al-Dhahabi did not mention this in his summary."  

«كَانَ الرَّجُلُ يُحَالِفُ الرَّجُلَ لَيْسَ بَيْنَهُمَا نَسَبٌ لِيَرِثَ أَحَدُهُمَا الْآخَرَ» فَنَسَخَ اللَّهُ ذَلِكَ بِالْأَنْفَالِ {وَأُولُو الْأَرْحَامِ بَعْضُهُمْ أَوْلَى بِبَعْضٍ فِي كِتَابِ اللَّهِ} [الأحزاب 6] سكت عنه الذهبي في التلخيص