Many modern “New Testament” churches claim that “they only go by the Word of God,” that their authority is the New Testament. Except, for the actual New Testament church, their authority was Jesus. The New Testament hadn’t been written yet.
However, if you want your authority to be a book and not a person, you’ll probably need help interpreting the book. If understanding God’s Word depends on human intelligence, you’ll probably need more intelligence than you have.
Fortunately, there are theologians who could take the place of Jesus in your church. Especially the dead ones, who aren’t around to protest. Because if John Calvin visited our churches, he might repeat what he said before, “Since…there are many who are cold and slow in the duties of love…it shows us how far we still are from the light of faith.” Or perhaps, “This recognition of him consists more in living experience than in vain and high-flown speculation.” I hate to think what Martin Luther or John Wesley might say.