What are the requirements for specifying the installments and their due dates in a kitabah contract?
General Chapter
Al-Mughni
Book of Mukātaba (Contractual Manumission)
Primary text
The installments ('nujum') must be specified, and the amount due for each installment must be known. Equality between installments or equality in the amount paid in each installment is not stipulated. A contract specifying the total amount over ten years, with one hundred due each year, or specifying different amounts at defined points (e.g., one hundred after five years and the rest at the end of ten) is permissible. If one states 'you pay one hundred every year,' it is permissible; the due date for each hundred is the end of that specific year.
Supporting text
The view of Al-Qadi and the companions of Al-Shafi'i suggests that specifying payment 'every year' without explicitly stating the time within the year is invalid. However, the statement of Barirah (paying one *awqiyyah* every year) supports its permissibility. If the term is linked with the particle 'fi' (in), the payment is due at the end of the period; if linked with 'ila' (until), it is due at the beginning of the period.