Romans 12:2

And do not be conformed to this world (any longer with its superficial values and customs), but be transformed and progressively changed (as you mature spiritually) by the renewing of your mind (focusing on godly values and ethical attitudes), so that you may prove what the will of God is, that which is good and acceptable and perfect (in His plan and purpose for you).

 

As we increase in the revelation of the word of God, a separation from worldly ideas and ideals becomes natural.  As the world departs from Godly values and attitudes, the Bible remains a stable source of the truth.  We may begin to naturally no longer watch, listen to, or allow any influence from those influences that speak against the word of God.