16. In addition to this, He did not appoint this twofold form by itself, but gave His true natural flesh, in the bread, and His natural and true blood, in the wine, that He might give us a really perfect sacrament or sign. For just as the bread is changed[17] into His true natural body and the wine into His true natural blood, so truly are we also drawn and changed into the spiritual body, that is, into the fellowship of Christ and all saints, and put by this sacrament in possession of all the virtues and mercies of Christ and His saints; as was said above[18] of a citizen who is taken and incorporated into the city and the protection and freedom of the entire community. Therefore He instituted not simply the one form, but the two separate forms, His flesh under the bread, His blood under the wine, to indicate that not only His life and good works, which are represented by His flesh and which He accomplished in His flesh, but also His passion and martyrdom, which are represented by His blood and in which He shed His blood, are all our own, and by being drawn into this fellowship we may use and enjoy them. 17. All this makes it clear that this holy sacrament is naught else than a divine sign, in which Christ and all saints are pledged, granted and imparted, with all their works, sufferings, merits, mercies and possessions, or the comfort and strengthening of all who are in anxiety and sorrow, and are persecuted by the devil, sin, the world, the flesh and every evil; and that to receive the sacrament is nothing else than to desire all this and firmly to believe that it shall be done. [Sidenote: The Third part of the Sacrament: Faith] There follows the third part of the sacrament, that is faith, on which all depends. For it is not enough to know what the sacrament is and signifies. It is not enough that you know it is a fellowship and a gracious exchange or blending of our sin and suffering with the righteousness of Christ and His saints; you must also desire it and firmly believe that you have received it. Here the devil and our own nature wage their fiercest fight, that faith may by no means stand firm. There are those who practice their arts and subtleties to such an extent that they ask where the bread remains when it is changed into Christ's flesh, and the wine when it is changed into His blood; also in what manner the whole Christ, His flesh and His blood, can be comprehended in so small a portion of bread and wine. What does it matter? It is enough to know that it is a divine sign, in which Christ's flesh and blood are truly present--how and where, we leave to Him.[19]