The ruling when a master specifies forgiveness of the largest installment payment.
General Chapter
Al-Mughni
Book of Mukātaba (Contractual Manumission)
Primary text
If the master says, 'Forgive him his largest installment,' they are obliged to forgive the one greatest in monetary value, as 'largest' refers to magnitude. If the instruction is, 'Forgive him the majority of his installments,' they must forgive more than half. For example, if there are five installments, three are forgiven; if six, four are forgiven. There is an alternative interpretation that this refers to the single largest installment in value, akin to saying 'his largest installment.' If the installments are equal, the first interpretation prevails.
Supporting text
There is a possibility that 'the majority of his installments' refers to the one greatest in monetary value, similar to the phrasing for 'his largest installment.' If the installments are equal in value, the primary interpretation prevails.