Firstly, almost all the protestant systematic theological writes agree that the basis for the inspiration of Scripture is found in 2 Timothy 3:16-17. This teaches that God Himself has revealed His Word for the church’s and believer’s benefit, and for His glory. The fact that the Scripture has been inspired by God, means it cannot be wrong, or contradictory. 2 Peter 1:21 expresses that no prophecy has ever been made by the will of man, rather, God spoke through, or revealed to select men the necessary words to record as His Word, and they were carried along by the Holy Spirit throughout the entire process. Therefore, God used the abilities and personalities of the human writers, but it did not hinder His communicated His message.
Secondly, the authority of Scripture points to God’s rule through His Word. In other words, to deny or reject the Scriptures, is to deny and reject God directly. God is sovereign, and therefore, whatever His Word commands, ought to be obey by His followers. God reveals His character, and work to us through Scripture. He also communicates His will and desires through His Word.
Thirdly, the clarity of Scripture, also known as perspicuity, means that God’s Word is clear and understandable, so that it can be interpreted in literally for the believer’s edification. Therefore, the Bible is clear in all that is necessary for us to know the truths about sin, salvation, and everything pertaining to life & Godliness. This does not mean that the reader will understand everything clearly, as our finite minds cannot fathom the infinite, but it does mean that God’s Word is revealed plainly.
Fourthly, the necessity of Scripture, or the sufficiency of Scripture, means that God has, through His Word, revealed all that is needed to equip believers. It means that Scripture is enough to deal with sin, salvation, and whatever else counsel that may be necessary. Back to 2 Timothy 3:16-17, it means that Scripture is profitable for teaching, for reproof, for correction, and for training in righteousness, so that the man of God may be complete, and equipped for every good work. The Reformer also coined the phrase ‘sola scriptura’ based on this doctrine, emphasizing that the Bible alone is sufficient.