It is the hadith of Sayyida Aisha (may Allah be pleased with her), when she wanted to free Sayyida Barirah (may Allah be pleased with her), but her owners set the condition that the wala’ (right of inheritance/loyalty) would remain with them. But the Noble Prophet (peace and blessings be upon him) said: Buy her and set her free; the wala’ belongs only to the one who sets free.
It is also narrated from Sayyiduna Jabir bin Abdullah, may Allah be pleased with him, that the Messenger of Allah, peace and blessings be upon him, said: Whoever sells a slave and the slave possesses some wealth, then that wealth will belong to the seller, and any debt of the slave will also be the responsibility of the seller, unless the buyer stipulates otherwise.
Hadith Referenceالفتح الربانی / أبواب الشروط فى البيع / 5915
Hadith Gradingمحدثین:صحیح
Hadith Takhrij«حديث صحيح۔ أخرجه ابوداود: 3435، (انظر مسند أحمد ترقيم الرسالة: 14325 ترقیم بيت الأفكار الدولية: 14376»
Brief Explanation
Benefits: … The fundamental issue is that one must have knowledge of the prohibited forms and conditions of trade. Every condition that does not contradict any clause of the Shari‘ah and from which the Shari‘ah has not prohibited, will be permissible.