In biblical times, the sea was often thought of as being wild and savage (Acts 27:1–44; 2 Corinthians 11:25–26). The mention of wild waves draws attention to the untamable and uncontrollable nature of the sea, with foam being a metaphor for the shameless deeds of the heretics. The implication is that the heretics have no regard for honour, they are unbound by moral standards. They are out of control, flaunting their deeds rather than having a sense of shame for their conduct.1
13 wild waves of the sea, casting up the foam of their own shame; wandering stars, for whom the gloom of utter darkness has been reserved forever.