The Bible is its own source of authority.

One criticism of the Christian belief that the Bible is God’s Word is that we ultimately have to rely on the Bible itself to support the claim. It’s in the Bible that God tells us that He’s responsible for the content of the Bible. We can look to other types of evidence to verify the accuracy of the Bible, but ultimately, the Bible is its own authority. However for Christians, another factor comes into play, and that’s conviction. Those who embrace the Bible as true will often talk about the fact that the Bible is unlike any other book, and that as they read it, they come to believe it. The Bible teaches that the Holy Spirit makes the words of Scripture come alive in the hearts of those with faith to believe.