Chemnitz takes up the second point and issue with the teaching of the sacramentarians, (code for those who teach contrary to the simple words of institution.) the problem is the sacramentarians teach that the true mediator between man and God is the divinity of Christ, not his human nature. In fact in dealing with the Lord’s Supper we are told that it is the deity of Christ that serves as the medium(the means by which) we are joined to the flesh of Christ. Lutherans teach the exact opposite. Why? Because : “there is one God, and there is one mediator between God and men, the MAN Christ Jesus.” (1 Tim. 2:5 (ESV) There is a reason God became man in Jesus Christ. In order to mediate for us he had to become one of us. In order to represent us, he had to be one of us. In order to die in our place he had to become one of us. So it is not the deity that connects us to the humanity. But it is his humanity (and all that entails, including his flesh and blood which are essential to humanness) that serves as the connection, the bridge, the medium between us and the deity. As Chemnitz puts it: “He assumed our nature in order that through that which is related to us and consubstantial with us the Deity might deal with us.”
Again we see that this is not any ordinary theological argument over who can parse a text better. It isn’t just a splitting of hairs. At the heart of this argument is the gospel itself. The arguments raised against the belief in the simple and natural meaning of the words of institution, that in the Lord’s Supper we eat the body and drink the blood of Christ, are attacks on the Gospel. These arguments either question the humanity of Christ, or the deity of Christ. We need Christ to be both God and Man, fully God and fully man, 100% both. If he isn’t 100% both then we do not have a prayer. If Christ can’t make his body and blood be present where he says it is present, then he isn’t God. All things are possible for God. But it is the humanity of Christ, that mediates for us. Therefore it is his humanity that he gives us with his flesh and his blood.