One of the great slogans of the sixteenth-century Reformation against the Roman Catholic church was the Latin phrase sola scriptura, meaning the “Bible alone”. However, like any slogan that summarises something, it has been misunderstood. For example, sola scriptura does not mean that the Bible is the only authority for believers. What then did the phrase sola scriptura mean at the time of the Reformation? It was particularly used by Catholics like Albert Pighius (1490-1542) and Johann Dietenberger (c. 1475-1537) to encapsulate three points the reformers affirmed about the Bible.
Firstly, sola scriptura meant Scripture was the supreme authority over the church. It did not mean Scripture was the only authority. Luther, Calvin, and the other reformers used other authorities like reason and tradition. They developed arguments using logic (reason) and learned from the writings of past Christians (tradition) as they explored the Bible. Yet the Bible was the supreme authority that ruled reason and tradition because Scripture alone was infallible precisely because it is God’s word. All other authorities (including church leadership) were fallible and must submit to Scripture. As Heinrich Bullinger said: “As God’s word is confirmed by no human authority, so no human power is able to weaken its strength”.
Sola Scriptura meant Scripture was the supreme authority over the church. The Bible ruled reason and tradition because it alone was infallible as God’s word. All other authorities (including church leadership) were fallible and must submit to Scripture.
Why was the supreme authority of Scripture an issue at the Reformation? A variety of medieval theologians believed that the institutional church’s leadership, the bishops headed by the Pope (technically called the “magisterium”), were the true interpreters of Scripture. This effectively placed the teaching authority of the bishops over Scripture itself. The magisterium then could not be questioned. A turning point was Martin Luther’s famous debate with John Eck (1486-1543) at Leipzig in 1519. There it dawned on Luther that the magisterium could be in error, because the Council of Constance (1415) had wrongly put John Hus to death. The supreme authority of Scripture served to keep church leadership accountable.
The second aspect to sola scriptura was the sufficiency of Scripture. The Catholic church in the sixteenth century affirmed that Scripture needed supplementation with various rituals and beliefs not be found in Scripture. As John Eck put it: “not everything has been clearly handed down in the Sacred Scriptures”. In response the reformers argued that, whilst there were many truths of science and history that are not in Scripture, the Bible is sufficient for final salvation. Scripture equips believers with all that is needed to be saved and persevere to ultimate salvation. They proved this with the words that sum up John’s gospel:
Jesus performed many other signs in the presence of his disciples, which are not recorded in this book. But these are written that you may believe that Jesus is the Messiah, the Son of God, and that by believing you may have life in his name. (John 20:30–31, NIV)
John’s Gospel (which assumes the authority of the OT) in itself is sufficient for salvation. Hence, any other NT book added to it, only increases an already sufficient collection of books.
The reformers used the sufficiency of Scripture against a morass of rituals (e.g. not eating meat during Lent) and beliefs (e.g. the immaculate conception of Mary) had developed over the centuries. The reformers saw the burden this tangle was on believers. For example, many priests found celibacy unnecessarily oppressive. So, reformers like Huldrych Zwingli (1484-1531) questioned many medieval rites and opinions because they were not in Scripture and so they should not be imposed on Christians.
The clarity of Scripture denoted that any person could read Scripture for themselves and discover the basic way of salvation. It was the clarity of Scripture that helped drive the reformers to translate the Bible into the common tongue. Because Scripture was, in William Tyndale’s words, even for the ‘ploughboy’.
The third element of sola scriptura is the clarity of Scripture. This did not mean that all of Scripture was crystal clear to every Christian. It also did not signify that pastors and teachers were not needed to help laypeople understand Scripture (Eph. 4:11-12). The clarity of Scripture denoted that any person could read Scripture for themselves and discover the basic way of salvation. The reformers did agree that parts of Scripture were difficult to understand. But these passages did not threaten the sufficiency of Scripture. Rather, the unclear parts of Scripture were to be interpreted in light of its clear parts. Indeed, it was the clarity of Scripture that helped drive the reformers to translate the Bible into the common tongue. Because Scripture was, in William Tyndale’s words, even for the “ploughboy”. Laypeople needed to be fed with God’s word, and they were required to keep preachers accountable with an open Bible in their hands. Tyndale believed this so firmly that he lost his life for translating Scripture into the common tongue.
Sola scriptura is a simple phrase. But contained in it, are three critical truths: the Bible is the supreme authority, sufficient, and clear. All three are essential to the life of God’s people.
 Bullinger, De Scripturae Sanctae 8, Heinrich Bullinger, De Scripturae Sanctae Authoritate, Certitudine, Firmitate Et Absoluta Perfectione (Zurich: Christoffel Froschouer, 1538), 20a.
 Eck, Enchiridion 4, Enchiridion of Commonplaces Against Luther and Other Enemies of the Church, 46.