William Burkitt on Jude 1:23

By this the apostle means every thing that doth defile, though in the least degree; he forbids all affinity and nearness to the errors and vices of these sinners, implying that some sinners are so filthy and unclean, that there is no keeping company with them without defilement; and intimating that Christians in their conversing with erroneous or vicious persons, whom they labour to recover, should take great care that they be not corrupted nor debauched by them, they being only to deal with them as physicians, not as companions. Hating the garment spotted with the flesh.