When a true doctrine is held to by a series of Bible verses that bear upon a topic, a person is then led to believe that such a doctrine is true regardless of the difficulty that doctrine imposes on one’s intellect. The doctrine of Sola Scriptura (Scripture alone) is one in particular. This doctrine is assumed in the Bible. The fact that it is presupposed and/or assumed doesn’t mean that it is false, nor unfounded. Take for instance the doctrine of the Holy Trinity. There is not one single passage that teaches every aspect of the mystery of the Trinity, and yet one is led to conclude this vital doctrine after looking at a series of Bible verses that bear upon each and every aspect of the Trinity. Unless God revealed this doctrine to mankind, we would have never known the Triune God. Another great assumption is the existence of God. The Bible goes no further in proving the existence of God than simply declaring that “In the beginning God…” (Gen. 1:1). That God exists is Biblically assumed. No one (except for atheists and/or agnostics) challenges the existence of God. A doctrine is both true and Biblical whether it is taught by the Scriptures directly and/or from assumption. The issue of the exclusive authority of Scripture is similar. We readily admit that the Bible doesn’t say: “Scripture alone is the final rule of faith and practice” but we also acknowledge that when a person examines Biblical verses that bear upon the topic of the Scriptures, one is led to conclude that the Bible alone is the final authority in matters of faith and practice. Other than physically examining Biblical evidence for holding to Sola Scriptura, there is a more important reason that as to why a person could understand the Scriptures to be his “final or ultimate authority,” – a reason that escapes a mere scientific examination of Biblical objectives. That would be nothing else than the role of the Holy Spirit’s internal witness which cannot and should not be ignored nor excluded (Rom. 8:16; 1 Cor. 2:12-14).
In 2 Tim. 3:16, the authority of the sacred Scriptures came directly from God Himself. The exclusive authority of the Scriptures rests on the fact that there is no other rule of faith (i.e. what and why we believe) that is “given by inspiration” except “all Scripture.” The sacred Scriptures bear the exclusive claim of divine origin via inspiration. The apostle Paul references nothing but “all Scripture” as being given by inspiration and because of this, it alone is profitable (or useful). Nothing beside or other than Scripture is recognized as being equally profitable. The nature of the Scriptures (i.e. God-breathed) leads to the function as the only infallible rule of faith and practice.
The Lord Jesus Christ appeals only to the Scriptures in spiritual battle against Satan (Matt. 4). He appeals only to the Scriptures in his teaching ministry (particularly in Matt. 5-7, over and against rabbinical teachings of His day), and having done so was recognized by the audience as one who taught “with authority” (Matt. 7:29). He appeals only to the Scriptures in v. 31 of Matt. 22 in correcting the false doctrine of the Sadducees. And as He was correcting them we should note that He equates the written word (“have ye not read”) with the very voice of God (“that which was spoken unto you by God”). He appeals only to the Scriptures in Luke 24:27 as He was instructing the disciples about Himself. He could have easily spoken about Himself from His own personal experience and yet he chooses rather to expound unto them the things concerning His self from the Scriptures. Christ consistently appeals only to the Scriptures to settle matters of faith, doctrine, and practice – we would do well to consider His example and His words in John 5:39, to “search the Scriptures.”