والذي أعْتَقَهُمْ رجل من العَرَب، والعربيُّ إنَّما يَمْلِكُ مَن لا قَرابَةَ بَيْنَهُ وَبَيْنَهُ مِن العَجَم، ِ فأجازَ النبي لهم الوصيةَ
The one who manumitted them was a Bedouin Arab, and Bedouin only owned non-Arabs with whom they had no ties of kinship, so the Prophet allowed the bequest in their favor