Does a contract of 'Mukataba' (conditional manumission) with one of two related women permit intercourse with the other?
Chapter on What is Prohibited to Marry and Combining Between Them and Other Matters
Al-Mughni
Book of Marriage
Primary text
The apparent view according to Al-Kharqi is that if a man enters into a contract of Mukataba with one of two related women, the other does not become lawful for him. This is reasoned by analogy with the case of the mortgaged woman, as he still retains a means to reclaim the right to use her without reliance on the status of the other woman.
Supporting text
The companions of Al-Shafi'i argue that the other woman becomes lawful because the first has become unlawful due to a cause he cannot immediately remove, similar to being legally married.