Series: Warning: Do Not Be Sluggish
Powers Of Discernment Are Trained By Constant Practice
 About this we have much to say, and it is hard to explain, since you have become dull of hearing.  For though by this time you ought to be teachers, you need someone to teach you again the basic principles of the oracles of God. You need milk, not solid food,  for everyone who lives on milk is unskilled in the word of righteousness, since he is a child.  But solid food is for the mature, for those who have their powers of discernment trained by constant practice to distinguish good from evil.
Big Truth: Powers Of Discernment Are Trained By Constant Practice
Solid food is for the mature, for those who have their powers of discernment trained by constant practice to distinguish good from evil. (5:14)
The Immature Are Sluggish, Satisfied To Stay
The Mature Are Active, Eager To Grow
 And we desire each one of you to show the same earnestness to have the full assurance of hope until the end,  so that you may not be sluggish, but imitators of those who through faith and patience inherit the promises.
to give prudence to the simple, knowledge and discretion to the youthProverbs 1:22
How long, O simple ones, will you love being simple? …
The beginning of wisdom is this: Get wisdom, and whatever you get, get insight.
Leave your simple ways, and live, and walk in the way of insight.”
Better was a poor and wise youth than an old and foolish king who no longer knew how to take advice.
 Him we proclaim, warning everyone and teaching everyone with all wisdom, that we may present everyone mature in Christ.  For this I toil, struggling with all his energy that he powerfully works within me.
2 Timothy 4:3–4
 For the time is coming when people will not endure sound teaching, but having itching ears they will accumulate for themselves teachers to suit their own passions,  and will turn away from listening to the truth and wander off into myths.