All Scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness, that the man of God may be complete, thoroughly equipped for every good work. - 2 Timothy 3:16-17
This verse is one of the interanal evidences for the reliability of the scriptures. For those of us who trust God and have faith that He wants to communicate with His people this is a verse that comfirms the authenticity of the scriptures this is a passage that builds our faith.
All scripture is given by the inspiration. Literally, all scripture is given by the breath of God as He breathed His word into men who recorded it for us.
If that is indeed true, and I trust that it is, then it is certain that His word is profitable for us. There may be any number of helpful resources. There are books and websites and commnetaries and sermons and seminars and Bible colleges and seminaries and all those are good and proper. But unless all of these things are based on the scriptures the profit is limited at best.
The study of the scriptures is what matures us and completes us. It corrects and reproves and teaches us in order to complete us.
And it is what equips us to do God's work. Since it is alive and powerful and sharper than a two-sided sword it is the tool we need to separate truth from error and hypocrisy and faithfulness.
We cannot over use the scriptures. We cannot have an overdependence on the scriptures.
Our problem is the opposite. For a lot of folks the only time they hear the scriptures is for a half hour or so on Sunday morning.
If things are profitable we normally go after them. Why is it any different with the scriptures?