There are many scriptures that directly imply that the scriptures are authoritative because they are the written word of God recorded by his power. Below are some major ones:
Isaiah 55:11 ESV
11 so shall my word be that goes out from my mouth;
it shall not return to me empty,
but it shall accomplish that which I purpose,
and shall succeed in the thing for which I sent it.
Matthew 22:29 ESV
29 But Jesus answered them, You are wrong, because you know neither the Scriptures nor the power of God.
Matthew 15:6 ESV
6 he need not honor his father. So for the sake of your tradition you have made void the word of God.
Matthew 4:4 ESV
4 But he answered, It is written,
Man shall not live by bread alone,
but by every word that comes from the mouth of God.
Mark 7:3 ESV
13 thus making void the word of God by your tradition that you have handed down. And many such things you do.
Acts 18:11 ESV
11 And he stayed a year and six months, teaching the word of God among them.
John 8:47 ESV
47 Whoever is of God hears the words of God. The reason why you do not hear them is that you are not of God.
John 10:35 ESV
35 If he called them gods to whom the word of God cameand Scripture cannot be broken
Luke 24:27 ESV
27 And beginning with Moses and all the Prophets, he interpreted to them in all the Scriptures the things concerning himself.
Acts 17:2 ESV
2 And Paul went in, as was his custom, and on three Sabbath days he reasoned with them from the Scriptures,
Acts 18:28 ESV
28 for he powerfully refuted the Jews in public, showing by the Scriptures that the Christ was Jesus.
Romans 1:2 ESV
2 which he promised beforehand through his prophets in the holy Scriptures,
1 Timothy 4:13 ESV
13 Until I come, devote yourself to the public reading of Scripture, to exhortation, to teaching.
2 Peter 1:20-21 ESV
20 knowing this first of all, that no prophecy of Scripture comes from someone's own interpretation.
21 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 3:15-16 ESV
15 And count the patience of our Lord as salvation, just as our beloved brother Paul also wrote to you according to the wisdom given him,
16 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.
Ephesians 2:19:20 ESV
19 So then you are no longer strangers and aliens, but you are fellow citizens with the saints and members of the household of God,
20 built on the foundation of the apostles and prophets, Christ Jesus himself being the cornerstone,
2 Timothy 3:16-17 ESV
16 All Scripture is breathed out by God and profitable for teaching, for reproof, for correction, and for training in righteousness,
17 that the man of Godmay be competent, equipped for every good work.
Why We Believe the Bible, Part 1 :: Desiring God Christian Resource Library