John Calvin on Jude 1:23

23. Hating even the garment. This passage, which otherwise would appear obscure, will have no difficulty in it, when the metaphor is rightly explained. He would have the faithful not only to beware of contact with vices, but that no contagion might reach them, he reminds them that everything that borders on vices and is near to them ought to be avoided: as, when we speak of lasciviousness, we say that all excitements to lusts ought to be removed. The passage will also become clearer, when the whole sentence is filled up, that is, that we should hate not only the flesh, but also the garment, which, by a contact with it, is infected. The particle καὶ even serves to give greater emphasis. He, then, does not allow evil be cherished by indulgence, so that he bids all preparations and all accessories, as they say, to be cut off.