To whom belongs the property (Mal) owned by a slave or female slave when his master sells him/her?
Chapter on Selling the Musarrah (Animal with milk retained in udder)
Al-Mughni
Book of Sales
Primary text
If the master sells his slave or female slave who possesses property, that property belongs to the seller (master), unless the buyer stipulates ownership of the property. This is based on the narration from Ibn Umar that the Messenger of Allah (peace be upon him) said: 'Whoever sells a slave who has property, his property belongs to the seller, unless the buyer stipulates it.' This is narrated by Muslim, Abu Dawud, and Ibn Majah. The basis is that the slave and his property belong to the seller; thus, when the slave is sold, the sale is restricted to him alone, similar to selling one of two slaves he owns.
Supporting text
If the buyer stipulates ownership, the property belongs to him, based on the hadith narrated by Nafi' from Ibn Umar from Umar ibn Al-Khattab, and judged accordingly by Shurayh. This view is also held by Ata, Tawus, Malik, Al-Shafi'i, and Ishaq. Al-Khiraqi stated this applies if the buyer’s intent was for the slave and not the property. This is the explicit position of Ahmad and the view of Al-Shafi'i, Abu Thawr, and Uthman Al-Buti. It means the intent of the sale is not to purchase the slave's property, but rather to maintain the property remaining with the slave, consenting to its existence in his possession. When this is the case, the stipulation is valid and enters the sale, whether the property is known or unknown, of the same kind as the price or otherwise, whether tangible or debt, and whether it equals, is less than, or more than the price.