Who is entitled to the increase or benefit gained from the sold item after the contract but before rescission?
Chapter on Selling the Musarrah (Animal with milk retained in udder)
Al-Mughni
Book of Sales
Primary text
If the increase is attached (muttasilah), such as weight gain, physical maturity, acquired skills (learning), pregnancy before delivery, or fruit before pollination, the buyer returns the item along with its growth because the growth follows the contract and its annulment. If the increase is separate (munfasilah) and derived from something other than the object's essence, such as earnings, rent, or gifts, these accrue to the buyer in exchange for guaranteeing the item. This is evidenced by the principle, 'The yield is contingent upon the guarantee' (Al-Kharaj bi al-Daman). This rule is supported by the Hadith narrated by Aisha, peace be upon her, stating that the Prophet, peace be upon him, ruled, 'The yield is contingent upon the guarantee' when a buyer sold an enslaved man, used him, found a defect, and then returned him. This is the undisputed position of Abu Hanifa, Malik, and Al-Shafi'i.
Supporting text
If the separate increase stems from the essence of the sold item itself, such as offspring, fruit, or milk, the buyer retains the increase and returns only the original object. This is the view of Al-Shafi'i.