MULTIPLYING TEACHERS

The "renewal in knowledge in the image of the Creator" Paul places at the center of Colossians is also at the center of a chiasm, bookended by a list of things to be PUT OFF (e.g. sexual immorality and covetousness) in verses 5-9 and a list of things to be PUT ON in verses 12-15:

12 Put on then, as God’s chosen ones, holy and beloved, compassionate hearts, kindness, humility, meekness, and patience, 13 bearing with one another and, if one has a complaint against another, forgiving each other; as the Lord has forgiven you, so you also must forgive. 14 And above all these put on love, which binds everything together in perfect harmony. 15 And let the peace of Christ rule in your hearts, to which indeed you were called in one body. And be thankful.

Up until now, the focus of the letter has been on what the Colossians already know and what Paul can add to their previous learning. Now he makes it clear that the next step is for the Colossians themselves to become teachers:

16 Let the word of Christ dwell in you richly, teaching and admonishing one another in all wisdom, singing psalms and hymns and spiritual songs, with thankfulness in your hearts to God. 

The ultimate test of whether a student has learned the material is not multiple choice, true or false, or short answer questions. 

The proof of learning is when the student can effectively transmit the material to others. 

Our modern churches give everyone weekly opportunities to "sing psalms and hymns and spiritual songs", but how often are church members challenged to teach each other?

In my experience, most adult believers don't feel comfortable teaching spiritual truths to the children of the congregation, much less their peers. 

What are the chances the author of Hebrews give the same admonition to modern believers as he gave to his original audience:

11 About this (Jesus as high priest) we have much to say, and it is hard to explain, since you have become dull of hearing. 12 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, 13 for everyone who lives on milk is unskilled in the word of righteousness, since he is a child. 14 But solid food is for the mature, for those who have their powers of discernment trained by constant practice to distinguish good from evil.