Hebrews 5:12-13 admonishes its audience for their immaturity: "You need milk, not solid food; for everyone who lives on milk, being still an infant, is unskilled in the word of righteousness."  The truth of this statement stings, but also aims us toward the goal: "Solid food is for the mature."  Being grown up, that's the goal.  And the mature, the text continues, are those "whose faculties have been trained by practice to distinguish good from evil."  Grown-up Christians can distinguish.  They can tell the difference.  They discern.  

This growth comes through practice.  "Trained by practice."  Think about every word of that phrase. 

So many of our life skills come through focused, purposeful repetition.  Training by practice.  Pick any skill.  There are no shortcuts that allow for us to dispense with repetitive practice.  The accomplished piano player never gets over drilling on the scale.  The serious...