R.C. Sproul summarized the legacy of the Protestant Reformation with these words “Every Christian has the right to interpret the Scriptures for themselves, but no Christian ever has the right to misinterpret the Scriptures” , How can you tell the difference? How do you know when somebody is misinterpreting the Scriptures? Who is to decide what is a “right interpretation”, and what is a “misinterpretation”? This is why we need an infallible teaching office.
Martin Luther famously said: “My conscience is captive to the Word of God …”, but pretty much everybody can claim the same, for example a Presbyterian can assure us all, that is ok to baptize our babies, because his “conscience is captive to the Word of God”. A Baptist can tell us exactly the opposite, that we should not baptize our babies, and that he is certain that that is what the Bible teaches because his “conscience is captive to the Word of God”. How can the consciences of two people be captive to the Word of God and contradict each other? How can we decide who is interpreting Scripture correctly? Our conscience is not the final arbiter to determine truth, so to say: ““My conscience is captive to the Word of God …” is not enough, this approach has only created disunity and schism for the last 500 years.