C.F.W. Walther wrote a letter to incoming members as to what he expects membership to entail. Interesting and relevant to our times. Found via Steadfast Lutherans.
A genuine member of a Lutheran congregation must have a thorough understanding of pure Lutheran doctrine or at least must desire to grow in the knowledge of it. Such a one will imitate the Bereans in searching the Scriptures daily, he will not lay aside his Catechism when he has completed his elementary school training, but throughout his life continue to review it in order that he may understand it better and become more thoroughly grounded in it. He will read other good orthodox books and periodicals to become ever more firmly established in the pure doctrine.
A member of a Lutheran congregation must be able to defend his faith and to prove its correctness from God’s Word. St. Peter writes, I Peter 3:15: “Be ready always to give an answer to every man that asks a reason of the hope that is in you with meekness and fear.” A sad state of affairs is revealed when members of a Lutheran congregation, asked about their faith, say, “You will have to ask my pastor about that.”
It is a settled fact that whoever is indifferent to false doctrine is indifferent also to pure doctrine and his soul’s salvation, and has no right to bear the name Lutheran and the name of Christ.