Finitum capax infiniti
“The finite is capable of the infinite.” The conviction that created, physical things (a man's body, bread, water, a spoken word) can genuinely bear God without being destroyed or emptied. The Reformed tradition denies this (finitum non capax infiniti), and that single disagreement is the root of most Lutheran–Reformed differences over the Supper, Christology, and the sacraments generally.
In Doctrine — What Lutherans teach, and where it differs from neighbouring traditions.