Is The Bible God's Word?

The validity of the Christian faith depends on the Bible being authentic, truly God’s words for mankind.  While the veracity and authority of Scripture is basic to the Christian faith, many Christians don’t know why they believe the Bible is God’s Word.  Based on the evidence – how it was written, what it says about itself, and the testimony of witnesses, the Bible is credible, divinely inspired, and authoritative.  How then should we respond?