Is marriage with the sister of a woman currently in the waiting period (*Iddah*) permissible?
Chapter on What is Prohibited to Marry and Combining Between Them and Other Matters
Al-Mughni
Book of Marriage
Primary text
The consensus is that the waiting period (*Iddah*) of one sister prohibits the marriage contract (*Nikah*) with her sister. This is established because the existing state of *Iddah* is an impediment that must be cleared before marriage can occur.