It’s the only written record that purports to be from life not of this world, or realm for that matter. It’s the only communication we have from someone untainted by wrath, avarice, sloth, pride, lust, envy, and gluttony.
This written record is special, in so far as it is self–referential. What does it say for itself?
Scripture reveals the power of God at work in throughout the ages.
Jesus said to them, “Is this not the reason you are wrong, because you know neither the Scriptures nor the power of God? Mark 12:24 English Standard Version (ESV)
Scripture bears witness of the work of the Lord Jesus Christ, the Author of eternal life.
You search the Scriptures because you think that in them you have eternal life; and it is they that bear witness about me, John 5:39 (ESV)
Scripture testifies to the death, burial, and resurrection of the Lord Jesus Christ witnessed by many then alive.
For I delivered to you as of first importance what I also received: that Christ died for our sins in accordance with the Scriptures, that he was buried, that he was raised on the third day in accordance with the Scriptures, and that he appeared to Cephas, then to the twelve. Then he appeared to more than five hundred brothers at one time, most of whom are still alive, though some have fallen asleep. Then he appeared to James, then to all the apostles. Last of all, as to one untimely born, he appeared also to me. 1 Corinthians 15:3-8 (ESV)
Scripture is the authoritative source and check for all preaching.
Now these Jews were more noble than those in Thessalonica; they received the word with all eagerness, examining the Scriptures daily to see if these things were so. Acts 17:11 (ESV)
Scripture was written for our instruction and encouragement leading to hope.
For whatever was written in former days was written for our instruction, that through endurance and through the encouragement of the Scriptures we might have hope. Romans 15:4 (ESV)
Scripture reveals truths once hidden from men and into which angels long to look.
Concerning this salvation, the prophets who prophesied about the grace that was to be yours searched and inquired carefully, inquiring what person or time the Spirit of Christ in them was indicating when he predicted the sufferings of Christ and the subsequent glories. It was revealed to them that they were serving not themselves but you, in the things that have now been announced to you through those who preached the good news to you by the Holy Spirit sent from heaven, things into which angels long to look. 1 Peter 1:10-12 (ESV)
Scripture, though written by men, finds its source and ultimate Author in God and has the full weight of His authority for equipping those following Him.
All Scripture is breathed out by God and profitable for teaching, for reproof, for correction, and for training in righteousness, that the man of God may be complete, equipped for every good work. 2 Timothy 3:16-17 (ESV)
Scripture, the prophetic testimony, comes from God. The Holy Spirit provides the prophets, as His representatives, not only visions but also words used to describe and interpret them.
…Knowing this first of all, that no prophecy of Scripture comes from someone’s own interpretation. For no prophecy was ever produced by the will of man, but men spoke from God as they were carried along by the Holy Spirit. 2 Peter 1:20-21 (ESV)
Scripture is God’s wisdom given through his apostles and prophets for our sakes, some of which is hard to understand. But we are not to be carried away with error. We are to obey that which we understand and grow in grace and knowledge of our Lord Jesus Christ.
…As he does in all his letters when he speaks in them of these matters. There are some things in them that are hard to understand, which the ignorant and unstable twist to their own destruction, as they do the other Scriptures. 2 Peter 3:16 (ESV)
Calvin comments on authority of the word in chapter 7 of his Institutes of the Christian Religion.