Sola scriptura (Latin ablative, "by scripture alone") is the doctrine that the Bible contains all knowledge necessary for salvation and holiness. Consequently, sola scriptura demands only those doctrines are to be admitted or confessed that are found directly within or indirectly by using valid logical deduction or valid deductive reasoning from scripture. However, sola scriptura is not a denial of other authorities governing Christian life and devotion. Rather, it simply demands that all other authorities are subordinate to, and are to be corrected by, the written word of God. Sola scriptura was a foundational doctrinal principle of the Protestant Reformation held by the Reformers and is a formal principle of Protestantism today (see Five solas).
During the Reformation, authentication of scripture was governed by the discernible excellence of the text as well as the personal witness of the Holy Spirit to the heart of each man. Furthermore, per sola scriptura, the relationship of Scriptural authority to pastoral care was well exampled by the Westminster Confession of Faith which stated:
VII. All things in Scripture are not alike plain in themselves, nor alike clear unto all; yet those things which are necessary to be known, believed, and observed, for salvation, are so clearly propounded and opened in some place of Scripture or other, that not only the learned, but the unlearned, in a due use of the ordinary means, may attain unto a sufficient understanding of them.
Here the phrase "due use of the ordinary means" includes appeals to pastors and teachers (Ephesians 4:11-14). As such, sola scriptura reflects a careful tension between the perspicuity (clarity) of Scripture necessary for its role as final authority, and the occasional need for its meaning to be revealed by exposition (Hebrews 5:12).
Beyond the Reformation, as in some Evangelical and Baptist denominations, sola scriptura is stated even more strongly: it is self-authenticating, clear (perspicuous) to the rational reader, its own interpreter ("Scripture interprets Scripture"), and sufficient of itself to be the final authority of Christian doctrine.
By contrast, the Roman Catholic, Eastern Orthodox, and Oriental Orthodox Churches teach that the Scriptures are not the only infallible source of Christian doctrine. In their view "the Church 'does not derive her certainty about all revealed truths from the holy Scriptures alone. Both Scripture and Tradition must be accepted and honoured with equal sentiments of devotion and reverence.' The Tradition here in question comes from the apostles and hands on what they received from Jesus' teaching and example and what they learned from the Holy Spirit. The first generation of Christians did not yet have a written New Testament, and the New Testament itself demonstrates the process of living Tradition." These churches also believe that "'he task of giving an authentic interpretation of the Word of God, whether in its written form or in the form of Tradition, has been entrusted to the living teaching office of the Church alone'", in part because it was the Church that selected which books were to be in the biblical canon. Protestants believe instead that the Church passively recognized and received the books that were already widely considered canonical.