The Prophet ﷺ said, "The mudabbar slave is to be freed from the one-third portion of the estate."Ibn Majah said, "I heard Uthman, meaning Ibn Abu Shayba, say, 'This is a mistake,' referring to the hadith that the mudabbar is from the one-third."Abu Abdullah said, "It has no basis."
حدثنا عثمان بن أبي شيبة حدثنا علي بن ظبيان عن عبيد الله عن نافع
أن النبي ﷺ قال المدبر من الثلث قال ابن ماجة سمعت عثمان يعني ابن أبي شيبة يقول هذا خطأ يعني حديث المدبر من الثلث قال أبو عبد الله ليس له أصل
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[Its chain of transmission is very daif]. Bayhaqi reported it, 10/314, through the route of Ali bin Zubyan from him, and he is daif as stated in Taqrib and elsewhere, and he retracted his marfu attribution of it in the narration of Shafii, and the mawquf version is the sahih one. The marfu version has a corroborating witness that is very daif, found in Bayhaqi and elsewhere, and it also has a mursal corroborating witness that is likewise daif.