Those who regard lying vanities forsake their own mercy.
The prophet's deep-seated hatred of idolatry appears in this.  He had just observed the distressed mariners each appealing to his god; but, as yet, Jonah's attitude toward them would appear to be colored by that detestation in which all the Jews held other peoples.  That this was the case appears in Jonah's displeasure when the Ninevites actually repented and were spared by the Lord.