ectypal.net

The animating concern of both Luther and Zwingli was rooted in their understandings of salvation, not the Supper in isolation. For Zwingli, the idea of a physical presence of Christ in the Supper shifted the locus of faith from the spiritual, immaterial, truly saving "reality" - Christ - to a visible, material object incapable of bearing salvation. For Zwingli, Luther's position threatened the central Christian affirmation that salvation is to be sought in Christ alone, sola fide, not in anythingsdf on this earth. For Luther, Zwingli's rejection of Christ's personal presence in the Eucharist ruled out the only hope for salvation. Recognizing the "poison" of Andreas Bodenstein von Karlstadt, Luther perceived in Zwingli's spiritualism a rejection of the divinely ordained connection between the outer Word and the sacraments as vehicles of inner grace.