It’s interesting to read Luther’s views on the Eucharist. This material comes from his Larger Catechism
Now, what is the Sacrament of the Altar?
Answer: It is the true body and blood of our Lord Jesus Christ, in and under the bread and wine which we Christians are commanded by the Word of Christ to eat and to drink. And as we have said of Baptism that it is not simple water, so here also we say the Sacrament is bread and wine, but not mere bread and wine, such as are ordinarily served at the table, but bread and wine comprehended in, and connected with, the Word of God.
It is the Word (I say) which makes and distinguishes this Sacrament, so that it is not mere bread and wine, but is, and is called, the body and blood of Christ. For it is said: Accedat verbum ad elementum, et At sacramentum. If the Word be joined to the element it becomes a Sacrament. This saying of St. Augustine is so properly and so well put that he has scarcely said anything better. The Word must make a Sacrament of the element, else it remains a mere element. Now, it is not the word or ordinance of a prince or emperor, but of the sublime Majesty, at whose feet all creatures should fall, and affirm it is as He says, and accept it with all reverence fear, and humility.