Mathew 6:25

Therefore I tell you, stop being worried or anxious (perpetually uneasy, distracted) about your life, as to what you will eat or what you will drink; nor about your body, as to what you will wear. Is life not more than food, and the body more than clothing.  

Our thoughts can keep us busy if we don’t guard them. Suppose we take a thought and continue to think on something we eventually do that thought whether it is a worry, fear, or faith. An idea isn’t real because we think it!  We make it real by speaking and acting upon it.  So cast down fear, worry, doubt and unbelief and only take the thought that builds us up on the inside.