There was a law in Tokyo about 1900 that no foreigner could take up residence there unless he had a "substitute." There were natives who hired themselves out for this purpose. If the foreigner broke any law, the substitute suffered the penalty for it, even if the penalty were death. In a similar way, our standing before God and his law is only obtainable through the substitutionary work of His Son. And this substitutionary work is obtained without any fee—only faith in Him.