sola Scriptura - Scripture Alone

When the Reformers used the words sola Scriptura they were expressing their concern for the bible's authority, and what they meant to say by those words is that the bible alone is our ultimate authority - not the pope, not the Church, not the traditions of the church or church councils, still less personal intimations or subjective feelings, but Scripture only.

Sola Scriptura has been called the formal principle of the Reformation, meaning that it stands at the very beginning and thus gives form or direction to all that Christians affirm as Christians. Evangelicals abandon sola Scriptura when they reinterpret the bible to fit modern notions of reality or ignore it on the basis of supposed private divine revelations or leadings.

Unfortunately, it is possible to believe that the bible is the inerrant Word of God, the only infallible rule of faith and practice, as many if not all evangelicals claim to do, and still effectually to repudiate it because we think that it does not work today and are convinced that other things need to be brought in to accomplish what the Bible cannot do.

Whatever Happened To The Gospel Of Grace? by James Montgomery Boice  pp.32-34
Whatever Happened to The Gospel of Grace?: Rediscovering the Doctrines That Shook the World