What is Martin Luther's approach to liturgical services in light of Paul Tillich?

Question

This article has a line that reads:

We would call Luther's approach an evangelical-catholic one.

It cites Paul Tillich's use of "catholic substance" or "protestant principle". Can someone briefly summarize this concept in regards to Luther's approach to conducting liturgies or ceremonial worship? In what ways did Luther criticize the Roman Mass?

Is it trying to talk about Luther's protestant principle in regards to the catholic substance of the Catholic church during Luther's time?

I realize that the following resource may be helpful.

Obedient Rebels: Catholic Substance and Protestant Principle in Luther's Reformation. By Jaroslav Pelikan.

Dr. Pelikan both deepens our understanding of the Lutheran Reformation and contributes greatly to modern ecumenical dialogue. He describes "Catholic substance" as ". . . the body of tradition, liturgy, dogma, and churchmanship developed chiefly by the ancient church and embodied (but not exhausted) for Luther in the Roman Catholic Church of his day." "Protestant Principle" is understood as "the criticism and reconstruction of this Catholic substance . . . carried out in the name of the Christian gospel and with the authority of the Bible." For this union of "Catholic Substance" and "Protestant Principle" resulted the Protestant Reformation.

Answer 1

I think the answer can be found in the article you have linked.

On Page 129 for example, there's a description of how Luther broke up the unity of the eucharistic prayer:

Luther's recension of the Canon of the Mass is more controversial. How much Luther can be held responsible for breaking up the unity of the eucharistic prayer and how much late medieval additions had already destroyed its unity is debatable. Luther admitted there were sacrificial aspects of the Eucharist. However, he judges Roman Catholicism's stress on the Eucharist as "a good work we offer to God" to be totally wrong. In his Treatise on the New Testament, Luther states: "It is not we who offer Christ, but Christ who offers us. . . . We offer ourselves as a sacrifice along with Christ . . . he takes up our cause . . . and offers himself for us in heaven. . . . We offer our whole selves, our need, praise and thanks in Christ and through Christ; and thereby (through faith) we offer Christ to God, that is, we move Christ and give him occasion to offer himself for us and to offer us with himself." Because it was offered silently, Luther could omit most of the Canon of the Mass without upsetting the people.

The rest of the paragraph you've quoted from page 127 I think gives us further context:

We would call Luther's approach an evangelical-catholic one. He believes that unless God should provide a better liturgy, the Church must stick as closely as is evangelically possible to the liturgies of its past. Worship can and must express some continuity with the Church of the past, since the Gospel had never completely vanished from it. In short, Luther always remained closer to Rome than to the more radical reformers who wanted to discard the historic church: "Sooner than mere wine with the fanatics, I would agree with the pope that there is only blood."

Luther wanted to return the church to the way he believed it existed anciently. His greatest criticism of Catholic mass was obviously the way it had changed from the Church of the past, which is largely contained in his famous 95 theses.

In short, Luther preached the way he believed the Church of the past practiced. He took the tradition, liturgy, dogma, etc, of the Church (catholic substance) criticized it (95 theses) and reconstructed it (protestant principle) then preached his reconstructions, which he believed to be what the Church preached anciently.