What is the ruling on swearing oaths that one may say without meaning it, or by way of a threat?
No expiation is required for the oath that you do not mean; rather you say it as a matter of habit without intending it, because you are used to doing that and you do not intend to swear an oath as such. As for the oath that you intend and say deliberately, then expiation is required [if you break the oath], whether you meant to commit yourself to it or meant it as a threat.