John Wesley on 2 Kings 19:21

Virgin - So he calls Zion, or Jerusalem; because she was pure in good measure from that gross idolatry wherewith other people were defiled, which is called spiritual whoredom: and to signify, that God would defend her from the rape which Sennacherib intended to commit upon her with no less care than parents do their virgin daughters from those who seek to force and deflower them.