Basically what the pagans used to do swear by their idols so if they swear falsely it is swearing falsely by something false or even modern day false god’s.
what if you falsely swear falsely by falsehood falsely. Like, if you don’t really swear, but pretend that you do, and the thing to don’t swear is false, and you swear it by something false also, and really you only even pretended to swear by that false thing in your pretend swearing but really were pretend swearing by something true.