What is the ruling on saying "By divorce, you are sick," and is expiation required for the one who says it?

If you swore by divorce, truthfully describing the man as ill, then there is nothing upon you. However, if you swore falsely, then you have broken your oath, and your divorce has taken effect according to the majority of scholars. The lawful oath is swearing by Allah the Exalted, and swearing by divorce is among the oaths of the dissolute.