What is the ruling when a man says to his first wife: 'If you swear by divorcing your co-wife, you are divorced,' and then says the same to the second wife?
Chapter on Explicit Divorce and Others
Al-Mughni
Book of Divorce
Primary text
The second wife is divorced upon the man's statement to her. This is because his repetition of the condition to the second wife constitutes an oath contingent upon the divorce of the first wife, which serves as the condition for the divorce of the second wife to take effect. Subsequently, every time the man repeats this condition to the first wife, she is divorced, until the second wife has received three divorces. However, if he repeats the condition to the first wife after the second wife has been irrevocably separated (by three divorces), the first wife is not divorced because the condition requires an oath concerning the divorce of the second wife, who is no longer his wife.
Supporting text
If the man initially stated this to one wife and then repeated it to her, neither wife is divorced, as the statement is merely an oath contingent upon the divorce of her co-wife without attaching divorce to that oath itself.