Swearing by any thing which the Swearer thinks not God. For though men have sometimes used to swear by their Kings, for feare, or flattery; yet they would have it thereby understood, they attributed to them Divine honour. And that Swearing unnecessarily by God, is but prophaning of his name: and Swearing by other things, as men do in common discourse, is not Swearing, but an impious Custome, gotten by too much vehemence of talking.
An Oath Addes Nothing To The Obligation
It appears also, that the Oath addes nothing to the Obligation. For a Covenant, if lawfull, binds in the sight of God, without the Oath, as much as with it; if unlawfull, bindeth not at all; though it be confirmed with an Oath.