Is it valid to combine a contract of 'Kitabah' (manumission by installments) with a sale contract?
Chapter on Selling the Musarrah (Animal with milk retained in udder)
Al-Mughni
Book of Sales
Primary text
It is invalid to combine a contract of Kitabah with a sale, such as saying, 'I entered into Kitabah with you, and I sold you this slave of mine for one hundred per month, totaling one thousand.' This is invalid because the slave subject to Kitabah, prior to the completion of the installments, retains the status of a captive slave (ʻabd qan). Therefore, it is not valid for him to purchase anything from his master, nor can the master establish a debt (price) against his own slave.
Supporting text
Regarding whether the sale part of the invalid combined contract remains valid for its corresponding price after the Kitabah contract is annulled, there are two transmitted narrations (riwayatayn), which will be addressed in the section concerning the invalidation of a compound transaction (tafriq al-safqah). Abu Al-Khattab considered this scenario identical to the preceding ones, allowing for two differing viewpoints in all cases, though the position stated earlier is considered preferable.