[Quoting Luther:]I rate as one concoction, namely, as Sacramentarians and fanatics, which they also are, all who will not believe that the Lord's bread in the Supper is
His true natural body, which the godless or Judas received with the mouth, as well as did St. Peter and all [other] saints; he who will not believe this (I say) should let me alone, and hope for no fellowship with me
...
For that not only the godly, pious, and believing Christians, but also unworthy, godless hypocrites, as Judas and his ilk, who have no spiritual communion with Christ, and go to the Table of the Lord without true repentance and conversion to God, also receive orally in the Sacrament the true body and [true] blood of Christ, and
by their unworthy eating and drinking grievously sin against the body and blood of Christ, St. Paul teaches expressly. For he says,
1 Cor. 11:27: Whosoever shall eat this bread, and drink this cup of the Lord, unworthily, sins not merely against the bread and wine, not merely against the signs or symbols and emblems of the body and blood, but shall be guilty of the body and blood of the Lord Jesus Christ, which, as there [in the Holy Supper] present, he dishonors, abuses, and disgraces, as the Jews, who in very deed violated the body of Christ and killed Him; just as the ancient Christian Fathers and church-teachers unanimously have understood and explained this passage.