“All Scripture is God-breathed and profitable …for reproof…”
What does reproof mean? The Bible answers this.
John 16:8-11 “And He, when He comes, will convict the world concerning sin and righteousness and judgement; concerning sin, because they do not believe in Me; and concerning righteousness because I go to the Father and you no longer see Me; and concerning judgment, because the ruler of this world has been judged.”
[Reproof  and convict  are related Greek words meaning to refute and rebuke.]
Father, I love your word. I love how your word is proven by your word. It is internally self-verifying.