What is the ruling and expiation for swearing a false oath with the intention of not harming others?

It is permissible to swear falsely to avert harm from a Muslim if it is the only means, while using equivocation (tawriya) is recommended. There is a difference of opinion regarding the necessity of expiation (kaffara) for one who swears falsely to avert harm. According to the view that it is obligatory, it is: freeing a slave, or feeding ten poor persons, or clothing them. And whoever is unable to do so should fast for three days.