For John:
Like signing a contract, signing a confession--subscribing--is a statement of agreement.
In Confessional Lutheranism there is a distinction made between two different ways an individual may say he or she subscribes to the Lutheran Confessions.
A person may subscribe because he believes the Confessions are a correct interpretation of the Scriptures. This is called a "quia" subscription. Quia is the Latin for "because."
A person might also subscribe in so far as he believes the Confessions are a correct interpretation of the Scriptures. This is called a "quatenus" subscription. Quatenus is Latin for "in so far as."
If you have a group of teachers and pastors who maintain a quia subscription to the Lutheran Confessions you can be reasonably confidant that all those pastors and teachers are in basic agreement on the doctrine of Scripture.
Among a group of quatenus subscribers one can not be sure of what teaching any individual teacher may believe. With a quatenus subscription one pastor might deny the divinity of Christ, another might deny the Trinity, the virgin birth of Christ, or the penal substitutionary atonement of Christ. These are examples of heresies that place a person outside of Christianity.
Another teacher might deny the real presence in the Lord's Supper, or embrace the teachings of a limited atonement, acknowledge the authority of the Pope, or reject the office of the ministry. These are examples of teachings which place a person outside of Lutheranism.
A quatenus subscription is not really a subscription to the Confessions or to the doctrine of Scripture at all. It is simply a way for the wolves to hide among the flock.
A person who subscribes to the Lutheran Confessions "in so far as" the Confessions agree with Scripture might say that he can't subscribe to the words of men, only to the Word of God. This sounds pious. And the person might think it is humble and pious. But in the end it means that he disagrees with the Doctrine of Scripture as it is clearly taught in Confessional Lutheranism, and cannot be called a real Lutheran.
And if a person's disagreement has to do with the Three Ecumenical Creeds or the first three articles of the Augsburg Confession that person has rejected historical Christianity and cannot be called a Christian.
