משלי כט:ג פירוש: רש״י

but one who keeps company with harlots Heb. ורעה. He joins harlots to himself, as its apparent meaning. Our Sages, however, said: “He who says, ‘This tradition is acceptable, I will learn it, but this one is not acceptable, I will not learn it.’” The support [for this view] from the verse is that זונות throughout the Scriptures is not spelled fully [with two “vavim”] except this once only.