'Let the word of Christ dwell in you richly, in all wisdom, teaching and admonishing each other, in psalsm, and hymns, and spiritual songs, in grace singing in your hearts to the Lord.' (Colossians 3:16).
'And I am persuaded, my brethren -- I myself also -- concerning your, that you yourselves also are full of goodness, having been filled with all knowledge, able also one another to admonish.' (Romans 15:14).
'We proclaim him, admonishing every man and teaching every man with all wisdom, so that we may present every man complete in Christ.' (Colossians 1:28).
Essential to the proclamation of Christ is 'admonishing' every man who receives the message. Our role as ambassadors for Christ is not complete without this admonishment. Further, 'teaching' -- or imparting necessary information to the learner -- is distinguished from the admonishment. We know, then, that admonishment is something different from, and in addition to, telling men about Christ.
Paul tells the Romans and the Colossians that it is his expectation for every believer they they also 'admonish' one another. It is our duty to each other as 'ministers' one to another, as fellow members in the same body, to edify each other and build each other up. This admonishment, then, is not merely the province of the preacher and of the paid staff.
The Greek word for admonish is 'noutheteo' from which some derive the term 'nouthetic counseling.' The word is alternately translated 'admonish,' 'teach,' or 'exhort' but none of those truly capture the essence of what the term means. According to Jay Adams (The Christian Counselor's Manual, Competent to Counsel) nouthetic counseling is essentially confronting another believer with what is wrong, with some problem in that believer's life, and directing him with the authority of Scripture and of the Holy Spirit to change, to his betterment and to the glory of God.
Paul seems to indicate that this admonishment should be intentional and regular, and characterized by knowledge, wisdom, grace and the desire for the betterment of our brother. Instead, we tend to 'mind our own business' and leave our brothers to their own devices. We are slaves to the culture's idea that no one can tell anyone else how to live.
But God tells us otherwise. It is our duty to look after each other, protect each other, admonish each other, to speak the truth in love. By nouthetically counseling our brothers we are displaying the grace of God and participating in presenting each man complete in Christ.