What is the relationship between an orthodox "Confession of Faith" and soteric "conversion?" Many churches throughout history have had orthodox confessions of faith, but not all churches have stressed the importance of conversion: i.e., personally turning away from sin and toward Christ, exercising faith, love, and joy in Him. For example, historic Anglicanism confessed the Thirty Nine Articles of Faith; the Lutherans held to the Book of Concord; and Presbyterianism adopted the Westminster Confession of Faith. Each of those is an orthodox confession. Interestingly, since the 1600's all three of these denominations have adjusted their doctrinal affirmations, moving further and further away from the original statements. In the 1900's, that doctrinal apostasy resulted in church splits/schisms in all three denominations and ended with the old denomination affirming heresy and the new split returning to biblical orthodoxy.
I submit that one of the reasons for the doctrinal corruption in each of these cases is a lack of emphasis on conversion in all three denominations. There is a tendency in the paedobaptistic and externalistic denominations to try to "nurture" a corporate "faith," without insisting on individual, personal faith and love to Christ, without pressing the consciences of individuals, urging them to come to Christ. The eventual result of such neglect is an unregenerate denomination, which does not love the truth of biblical confessions of faith. Arid, loveless, intellectualism inevitably jettisons biblical confessions of faith and naturally adjusts church doctrine to conform to the ideals of unbelief.
An orthodox confession of faith only remains the confession of a church when that church stresses conversion and faithfully practices church discipline because only converted people love the truth. The unconverted will do anything they can to jettison it.
Therefore, the maintenance of a regenerate church membership is necessary for lasting confessional orthodoxy.