In, With, and Under: Sacramental Union, Not Transubstantiation

Holy Scripture clearly affirms the substantial presence of Christ in the Lord’s Supper. Yet, throughout the history of the Church, theologians have explained this presence in different ways. In Western Christendom before the Reformation, transubstantiation became the standard doctrine. The Fourth Lateran Council of 1215 dogmatized transubstantiation as official and infallible Church teaching. The Council of Trent reaffirmed transubstantiation after the Reformation was underway. 

Luther On Transubstantiation

Martin Luther distributing Holy Communion

Martin Luther took a different approach. In On the Babylonian Captivity of the Church, Luther rejected transubstantiation, while still allowing that it could be accepted as a theologoumena. Although he later became more opposed to the doctrine, Luther was never as hostile to transubstantiation as he was to the sacramental teaching of the southern Reformers. This was largely because although transubstantiation is a misguided account of the substantial presence of Christ in the Eucharist, it nevertheless affirms the core biblical teaching that Jesus is present in the elements of the Lord’s Supper.  

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Luther on Christ’s Real Presence in the Eucharist

Although Luther affirmed the substantial presence of Christ’s body and blood in the Eucharist, he disliked the doctrine of transubstantiation because it contradicts 1 Corinthians 10:16 which states that the bread and wine remain in the Lord’s Supper as the medium by which one receives Christ’s substantial body and blood.[1]  Luther considers the entire idea of transubstantiation an Aristotelian rationalization of the mystery of how the body and blood of Christ can become present through the bread and the wine.[2] 

In spite of this criticism of transubstantiation, it is interesting to note that Luther does not consider belief in the doctrine to be tremendously problematic and allows that people could still affirm transubstantiation as a theologoumenon.[3]  What is most important to the Reformer is that one affirms the substantial presence of Christ’s flesh and blood in the Lord’s Supper.  Although how one conceptually achieves this mysteriously physical presence is not unimportant, the main point for Luther is that one knows that Christ is substantially present in his body and blood “for you” (pro me).[4] 

This is why Luther was considerably less tolerant when it comes to the sacramental symbolicism of a figure like Zwingli.[5]  From Luther’s perspective, Zwingli ignores the divine promise that Christ’s flesh and blood will be present on essentially rationalistic grounds, namely, that physical bodies cannot be at more than one location at once.  As we have seen Luther rejects this logic and affirms that Jesus’ body remains a real body. However, it participates in God’s glory and can transcended the normal boundaries of physicality.[6]  After all, in the resurrection Jesus was able to walk through walls and appear and disappear at will.  Jesus’ body nevertheless remained a real body.  Christ could still invite Thomas to place his fingers in the nail holes of his very real hands and eat fish with the apostles.  Likewise, the mysterious supernatural quality of Christ’s body in the Lord’s Supper does not negate its real physicality or his genuine humanity. 

As we noted earlier, these differences between Luther and Zwingli on the sacrament are due in part to competing concepts of the communicatio idiomatum.[7]  Nevertheless, these differences also have implications regarding the nature of how the Word of God functions.  For Zwingli, the words of institution are signifiers that merely signify.[8]  Zwingli resolves the puzzle of how the signifiers “body and blood” can be validly applied to the signified “bread and wine” (which they do not match) through sacramental symbolicism.[9]  For Luther, divine words are not mere signifiers, but promises that effect what they speak.[10] This is the same principle that we have seen earlier in his views of confession and absolution.  Hence the words “this is my body . . . this is my blood” possess divine power to bring about the presence of Christ’s flesh and blood.[11]  Faith must simply trusts that God’s words perform what they promise.  To believe otherwise would be to trust in human reason over the God’s clearly stated promises.[12]


[1] LW 36:33-4.

[2] LW 36:34-5.

[3] LW 36:35.

[4] Paul Althaus, The Theology of Martin Luther, trans. Robert Schultz (Philadelphia: Fortress Press, 1966), 379.

[5] Lohse, Martin Luther’s Theology, 169-77; Sasse, This is My Body, 134-294.

[6] Thomas Davis,  This Is My Body: The Presence of Christ in Reformation Thought (Grand Rapids: Baker Academic, 2008), 41-64; Sasse, This is My Body, 148-60.

[7] Sasse, This is My Body, 148-54.

[8] See discussion in: Aaron Moldenhauer, “Analyzing the Verba Christi: Martin Luther, Ulrich Zwingli, and Gabriel Biel on the Power of Words,” in The Medieval Luther, ed. Christine Helmer (Tübingen: Mohr Siebeck, 2020), 53-6.

[9] Ulrich Zwingli, “On the Lord’s Supper,” in Zwingli and Bullinger, 175-238.

[10] Moldenhauer, “Analyzing the Verba Christi,” 57-61.

[11] LW 37:180-88.

[12] LW 37:131.


From the draft manuscript for Jack D. Kilcrease, Justification by Word (Lexham Press, forthcoming).