The Protestant Reformers’ slogan “sola Scriptura” means that Scripture alone is our court of highest authority. This should not be confused with “solo Scriptura”, which is the erroneous belief that truth is to be found only in Scripture and nowhere else. Scripture itself speaks of lesser courts of lower authority that Christians should obey: we should submit to the authority of pastors, government, and parents up to the limits of disobeying the highest authority of Scripture. [FOOTNOTE: Heb. 13:17; cf. 1 Tim. 5:17–20; 1 Pet. 2:13–15; cf. Acts 4:19; 5:29; Rom. 13:1, 5; cf. Acts 16:35–40.]
The Bible itself models the fact that there is at least some truth outside of the Bible when it occasionally quotes other books, such as the Book of Jashar and the Book of the Wars of the Lord. [FOOTNOTE: Josh. 10:13, 2 Sam. 1:18; Num. 21:14.] In quoting them, the Bible is not saying that they should be included as sacred Scripture but rather that they do contain some truth. Likewise, a mechanic, doctor, or computer programmer does not have to consult Leviticus to turn a brake drum, perform open-heart surgery, or make an addition to a software program.
Regarding the sufficiency of Scripture, the Bible and the Bible alone teaches a complete Christian worldview that includes what we need to know about God, how to come into relation with him, who Jesus is and what he did for our salvation, and what will happen at the end of history. One example is perhaps most clarifying in understanding the sufficiency of Scripture. Jesus tells the story of a man who died in unbelief and was suffering in torment. Jesus explains how the man in anguish had a conversation with Abraham across a chasm that separated those who had died in faith from those who had died in unbelief in the days prior to Jesus opening heaven. The man in anguish was concerned for his five brothers who remained alive and in unbelief. Luke 16:29–31 reports:
Abraham said, “They have Moses and the Prophets; let them hear them.” And he said, “No, father Abraham, but if someone goes to them from the dead, they will repent.” He said to him, “If they do not hear Moses and the Prophets, neither will they be convinced if someone should rise from the dead.”
Jesus was emphatically clear that the Scriptures alone are sufficient for all that is needed to know God and enjoy His salvation. As Abraham said in Jesus’ story, the Scriptures are even clearer and more compelling than the testimony of a man returned from death to give a personal report of the consequence for dying in unbelief.