What are some pitfalls of being passive in our spiritual life?

Dr. Joel Beeke explains in this video that it is important to be selective and be intentional about who and what you allow into your life. We only have a limited time on earth -- we cannot afford to waste the life that God has given to us. 

We must be mindful about what we listen or view. To maintain a healthy body, for instance, one must eat healthy foods and exercise, among other things. The same principle applies to maintaining a healthy spiritual life. We ought not to neglect to do things that will spiritually strengthen us or indulge in sin. 

Colossians 3:17 (NKJV) - "And whatever you do in word or deed, do all in the name of the Lord Jesus, giving thanks to God the Father through Him."