All Scripture is inspired by God and is profitable for teaching, for rebuking, for correcting, for training in righteousness, so that the man of God may be complete, equipped for every good work. 2 Timothy 3:16-17
The word inspired here means “breathed out by God”. Because Scripture comes from God himself, it is profitable in many ways, ultimately leading us to righteousness, maturity, and service. The phrase “all Scripture” here refers primarily to the Old Testament, but by implication it applies to the writings of the New Testament as well. What Paul is telling Timothy and by extension us is that the words written in the Bible (both Old and New Testament) though they were written by human authors were inspired by God. What that means is that God through the power of the Holy Spirit divinely inspired the author of each of the 66 books contained within the Bible. That is why the Bible is the most important tool in your arsenal as a follower of Christ. That is why you should be spending time on a daily basis reading and mediating on the Bible, because it is the very word of God and it is how you get to know God. That is why Paul wrote that the Bible “is profitable for teaching, for rebuking, for correcting, for training in righteousness, so that the man of God may be complete, equipped for every good work.” For you see the Bible can be used to teach. It can be used to correct and discipline. And it can be used to train a person in righteousness. And it is through all of this that God’s word equips you the Child of God to go out and do what you have been called by God to do.