Is the sale of a cat (harr) permissible?
Chapter on Selling the Musarrah (Animal with milk retained in udder)
Al-Mughni
Book of Sales
Primary text
The sale of a cat is permissible according to Al-Kharqi, Ibn Abbas, Al-Hasan, Ibn Sirin, Al-Hakam, Hammad, Al-Thawri, Malik, Al-Shafi'i, Ishaq, and the Ashab al-Ra'y (supporters of rational jurisprudence). The permissibility is based on the principle that sale is legislated as a means to attain needs and utilize permissible benefits. This allows everyone to benefit from what is in another's possession, thus the sale of anything whose benefit is permissible should be allowed.
Supporting text
There is a disliked view concerning the price of cats, narrated from Ahmad, Abu Hurayrah, Tawus, Mujahid, and Jabir ibn Zayd, favored by Abu Bakr. This view is based on a narration from Muslim where the Prophet (peace be upon him) rebuked the practice, and another narration from Abu Dawud where the Prophet (peace be upon him) explicitly forbade the price of a cat. This narration is considered Hasan by Al-Tirmidhi, though its chain has some instability.