Toward the very end of his life, Martin Luther addressed this question through a rather lengthy critique of the medieval church and its need for and a justification of its reformation. This was not Luther simply lambasting his opponents but searching the Scriptures for the marks of the one, holy, catholic, and apostolic Church. His answer is, then,
not a guess but based on Holy Scripture. If you read his words you will find typical Luther -- prodding, offending, and challenging but also comforting, teaching, and assuring. Near its end, Luther
identified what he called the seven marks of the Church. By these
marks, then, one can know where the Church is located (even though its full extent may not be visible to you). These marks are God’s Word; Holy
Baptism; the Sacrament of the Altar; the Office of the Keys; called
ministers; and prayer, praise and thanksgiving to God. To this list Luther appended a seventh mark of the Church: the true and sacred Cross (we might actually call this the Gospel itself).
In his 1539 treatise, On the Councils and the Church, Luther addresses what I as a Lutheran address on almost a daily basis and that which compels me to answer for me, for my ordination, and for my minister on behalf of and to the people of my parish. I hope and pray that I am not alone in this. It is the most urgent and relevant consideration we as Lutherans (and every serious Christian and Christian minister) should have. Where is the Church?
Rome is clear about this. For Rome the Church is where the Pope is and there is no Church not in communion with the Pope, not under his staff and authority, not under his vicarage. I will admit that as a Lutheran I would like to believe this. It would solve so many problems I face as a Lutheran and as a Christian in a world where churches are a flavor of the month and within each communion is such diversity of doctrine and practice as to render any commonality almost an exception. But as much as I would love this to be the case, it is not the answer of Scripture or even the witness of the earliest Christianity. How do you go from Ignatius' where the bishop is, there is the Church to the Roman claim of exclusivity (except, of course with respect to the Orthodox and even the Jews, with their own way to God's grace apart from Christ)?
Wherever the bishop appears, there let the people be; as wherever Jesus Christ is, there is the Catholic Church. Does this offend against Luther's seven marks or does this accord with them? Does the creed conflict with Luther's extended list or does it agree with them? How does Rome's claim of exclusivity fit within these marks and Ignatius' claim? These are things I wrestle with and I suspect many Lutherans and true Christians also do. I am not so sure that many within Rome struggle much with the answer to this question. I fear that this is a settled issue with them and the simple answer of the Pope has left them with an easy out.
This is certainly a reason why I am a Lutheran and why I have not swum the Tiber, so to speak. If Luther is in any way correct in the marks of the Church, then we should be able to judge the whole on the basis of its parts, its faithfulness to those parts. And it is in this arena where Rome comes up short. Rome is hardly a church of God's Word. Oh, yes, the Scriptures are read seriously within the mass but Rome has officially sided with the idea that the factual basis of what that Word says does not necessarily relate to its truth. Rome is surely not alone in this but how can any church desiring to be the Church countenance treating the Word of God as included in Scripture but not Scripture?
Holy Baptism is another problematic area. When the issue of a priest's baptism was addressed, Rome struggled to know how to deal with the deacon's straying from the script. You surely recall the story. But in the end, the failure of the deacon to say I baptize left the priest's ordination and all his sacramental presiding invalid. Is baptism rooted simply in this form? What about the East and its more ancient formula of You are baptized in. . . ? While none of this is pivotal it seems that Rome's preoccupation is with validity and licit sacraments more than Romans 6.
When it comes to the Sacrament of the Altar, Rome seems to suggest that the sacramental grace is apart from the eating and drinking but in sacrificial offering. Perhaps I am mistaken in this, I often am, but Rome equates the adoration of the Corpus Christi with its eating and drinking and there is no Scriptural warrant for this conflagration. Even then, the sacramental liturgy, especially in the Latin Mass, seems to see the faithful as disinterested spectators while the real action lies in the hushed tones of the priest at the altar. How does that accord with Scripture? I will not even begin to address the liturgical oddities and hurried masses that betray the reverence demanded by taking seriously what is happening within this Eucharist.
With the Office of the Keys we face the same problem -- how is this sacrament administered? While there is nothing wrong with and something salutary about encouraging the sinner seeking absolution to address the behaviors that make them vulnerable to temptation and wrong, emphasizing the satisfaction over the absolution dramatically changes the whole thing. I envy how normal confession is in Roman Catholicism but the penance assigned has become larger than the grace imparted.
For Rome, the ministry is all about the form. Apostolic succession has become a formality and line instead of a succession not only of office but of doctrine and teaching and preaching. I actually do have a couple of good Roman Catholic preachers whose sermons I listen to every now and then but the reality is that the sermon or homily is routinely the weakest part of the mass and that thing which the priest spends the least amount of his time upon -- listen in just about anywhere.
Finally, with its rushed pace and casual and irreverent attitude toward the things of God, what happens among Roman parishes in prayer, praise and thanksgiving to God so often pales in comparison to the reverence, enthusiastic singing, and strong vocal participation of the place where I serve. In this the question is rather simple: Does what we actually see in the worship and liturgical life of the Roman Catholic Church look like that which we expect of the One, Holy, Catholic, and Apostolic Church? I think you know my answer. Rome looks like the worst of Protestantism more than it looks like anything else.
Markers. I look for them. When I look to Rome, I find mixed signals in the words and a distinct lack of markers in the practice. So when it comes to the claims made, I have little recourse but to reject them because where I am, I do not see them lived out. This ought to the goal and purpose of every parish no matter the name -- we preach, teach, preside, and sing like the one, holy, catholic, and apostolic church.
We cheerfully maintain the old traditions made in the Church for the sake of usefulness and peace. We interpret them in a more moderate way and reject the opinion that they justify…. We can truly declare that the public form of the churches is more fitting with us than with the adversaries… Among us many use the Lord’s Supper every Lord’s Day. They do after they have been first instructed, examined, and absolved. The children sing psalms in order that they may learn. The people also sing so that they may either learn or pray… Among us the pastors and ministers of the churches are encouraged publicly to instruct and hear the youth. This ceremony produces the best fruit… In our churches all the sermons are filled with topics such as these: repentance; the fear of God; faith in Christ, the righteousness of faith, the comfort of consciences by faith; the exercises of faith; prayer, what its nature should be, and that we should be fully confident that it is powerful, that it is heard; the cross; the authority of officials and all civil ordinances; the distinction between the kingdom of Christ, or the spiritual kingdom, and political affairs; marriage; the education and instruction of children; chastity; all the offices of love. From this condition of the churches it may be determined that we earnestly keep Church discipline, godly ceremonies, and good Church customs.—Ap XV:38-44