2 Peter 3:17-18

Therefore, (let me warn you) beloved, knowing these things beforehand, be on your guard so that you are not carried away by the error of unprincipled men (who distort doctrine) and fall from your own steadfastness (of mind, knowledge, truth and faith), but grow (spiritually mature) in the grace of our Lord and Savior Jesus Christ. 

When we increase our knowledge of the Bible, we grow our spirits and renew our minds.  It is harder for us to be deceived when we have built ourselves up and practice our faith.  God gave us the Bible as a way to avoid the pitfalls of life.  By keeping our guard up, we can distinguish the good doctrine from the bad.