Does divorce occur if a husband swears to his wife that she will not speak to her sister's husband, and then she speaks to him intentionally or unintentionally?

The summary of the ruling on swearing an oath by divorce against the wife not to speak to her sister's husband, with details, is as follows:

- If the prohibition is for a clear reason, such as fear of corruption, there is no harm in the husband preventing her.

- If the husband intended for the divorce to occur when the wife speaks to her sister's husband, then divorce occurs at that time.

- If he only intended prevention, then this is an oath, and expiation is required for it.

- If the wife spoke to her sister's husband forgetting the oath, the preponderant opinion is that the divorce does not occur.

- Conveying greetings from the sister's husband and responding to them is not considered prohibited speech.

- Care must be taken to avoid speaking with the sister's husband in obedience to the husband, to avert divorce, and to adhere to hijab in front of non-mahram men.