I think “the meaning is obvious (or the same because it is the same scripture) is one underlying assumption of sola scriptura.
I think when Luther discovered that this was not the case, interpretative catechisms/confessions became necessary. And this revealed a problem with sola sciptura - really, almost regardless of the specific definition.
So the logic of sola scriptura is violated if you need another document that says what doctrine you get from scripture in order to be of the Reformed faith.
thanks for your reply
Ok, I think I understand your confusion. You are comparing apples and oranges.
Sola Scriptura NEVER clings to all of Scripture being understandable to every Christian. Simply put, Sola Scriptura means that Scripture is the sole rule of faith for the Christian.
The Confessions and Catechisms are not, in any way, given superior or equal status to Scripture. Rather they are a summery of essential doctrines of the Christian faith.
I can think of this working it’s way out in three ways.
1. It protects God’s people from erroneous teaching. Let’s say a pastor gets in the pulpit and preaches we are saved by out own works. A Saint in the congregation know this is wrong, but will have to through Scripture trying to remember how to refute that statement. Or he can just open his handy Confession/Catechism and then approach the preacher and ask if he heard the preacher right. If the preacher confirms what the member heard, the summery of Scripture can be used to bring charges in a church court.
2. While Scripture is the Sole Rule of faith, the confessions and Catechisms are useful for instructing children and new believers. The footnotes prove what is being taught.
3. Let’s say Bod stands up in a small group and proclaims an new understanding. Rather than pour through Scripture, the catechism easily refutes false views brought out in small groups. Now the other side of the coin what if members of a church or group start pouring false teaching on a member. The member can double check, quickly, if he is right or the group, without have to spend hours studying Scripture.