In 1520 Martin Luther explained the nature of faith using marriage as an illustration: "The third incomparable benefit of faith is that it unites the soul with Christ as a bride united with her bridegroom. By this mystery, as the apostle teaches, Christ and the soul become one flesh. And if they are one flesh and there is between them a true marriage ... it follows that everything they have they hold in common, the good as well as the evil. Accordingly the believing soul can boast of and glory in whatever Christ has as though it were his own."