There are those, some of them Lutheran, who complain all the time about stuff. They worry about liturgy which might become too important or even the catechism which they fear does not confront people with the authority of Scripture alone or ceremonies which might detract from the Word or attention to the fathers of the Church because they were not perfect. . . You get the idea. They just want Jesus and they want the Bible alone. That is enough.
As Lutherans we are all about Scripture being sufficient. The Word alone endures forever -- not the midrash or the Talmud or whatever Lutheran or other version you put next to it. That said, isn't it great that the Scriptures are not alone? For surely God has provided us with so much so that the Word is surrounded by the great company of saints, by the faithful witness of generations past, by creeds and confessions in which the Scriptural witness has been sharpened in conflict, and by the liturgy which prays and sings this Word back to the Lord with the voices of the faithful who believe it. These are gifts of God so that the Word is not like an island alone but a rich landscape that draws us into the Word and sends us forth from it.
Scripture is sufficient. That merely means that the Bible is enough revelation from God to save us and so that we might live under Him in His kingdom in the world but not of it until we live in His eternal kingdom. Scripture is not sufficient to answer every question we might have or to resolve every presumed conflict reason or science has with the Word. That is not because of the deficiency of the Word but because of that which lacks in minds that are not equal to Him and our best earthly wisdom is not His heavenly wisdom. We are fools for Christ -- at least according to the world and the Bible does not at all mitigate against this false judgment from those who cannot or will not see.
There is nothing lacking in Scripture which we need to know to be saved and to fulfill His calling and purpose in our lives. It is all there. Scripture is sufficient. And more than even this, Scripture is efficacious. It is not a word on a page but a living voice that continues to speak and things happen, just as creation was called into being through the Divine Logos. This revelation is enough. In many and various ways God spoke to His people of old but now He has spoken through His Son. Christ is the Word. All the Law and the Prophets testify to Him. This Word continues to be the force or means of grace through which He confronts our hearts with our sin and breaks through to build in us living faith to trust in Christ alone as Savior, Redeemer, and Lord. We do not need any additional revelation from God. Scripture is alone sufficient. But Scripture is not alone.
Sola Scriptura insists that Scripture is alone sufficient but it does not insist that the Bible exists in some sphere, isolated from those through whom it was written or apart from the company of the faithful who still believe its voice. Sola Scriptura is not a choice between the faithful witness, faithful creeds, and faithful confession and the Word but the Word in this context -- the great company of the faithful whose witness points us to Jesus, the Word made flesh in whom we beheld the saving glory of the Father and are saved.
Scripture has given us plenty enough but not every heresy or every gnosticism or every question is mentioned in Scripture. Yet within Scripture is the power of that Word to answer every heresy, every gnostic falsehood, and every question of what we are to believe and how we are to live (morality). That men come to different conclusions is not the fault of Scripture but can very well be our difficulty is accepting the catholic witness of truth that does not change. This is clearly the case when it comes to issues such as homosexuality or transgenderism or new definitions of marriage. It is not that Scripture has not spoken or that its answers are confusing or even that people have had different perspectives on those answers over time. It is clearly and plainly that some have decided that they did not like those answers or what Scripture has said and so they work to obfuscate and deny what Scripture has said, the Church has believed, and the faithful have confessed since the beginning.
We do not gain anything by treating Scripture as an island of words apart and by discounting or ignoring the witness of creed, confession, and faithful witness over time. Indeed, we are the poorer for it. God has provide this apostolic tradition living out in age after age -- not as substitute for His Word or even competitor but as complement. When Lutherans speak thus of sola Scriptura we speak in this way and not a naked or isolated Scripture. This does not at all detract from its sufficiency but rejoices as the richness of what God has provided so that we hear this Word from the Scriptures AND from the voices of the faithful through the ages. What a gift and blessing!!
It is not a question if Scripture is all we need but a recognition that Scripture, sufficient in and of itself, is not all we have. That is not to say that they are equal witnesses. They are not. But the witness of the catholic and apostolic tradition is not a trifle. It is substantial. Some churches have no place for this. Some churches emphasize this over and above the witness of Scripture. Some make their voices equal. We honor the witness of Scripture as unique and rejoice at the witnesses surrounding it. That is what a Lutheran means by sola Scriptura.