Charles Ellicott Commentary Deuteronomy 5:11

"Thou shalt not take the name of Jehovah thy God in vain: for Jehovah will not hold him guiltless that taketh his name in vain." — Deuteronomy 5:11 (ASV)

Take ... in vain. —Literally, You shall not put the name of Jehovah your God to vanity: i.e., to anything that is false, or hollow, or unreal. Primarily, it is false swearing that is forbidden here; but the extension of the principle to vain and rash swearing, or the light use of the Name without real cause, is sufficiently obvious.