15And let the peace that comes from Christ rule in your hearts. For as members of one body you are called to live in peace. And always be thankful.16Let the message about Christ, in all its richness, fill your lives. Teach and counsel each other with all the wisdom he gives. Sing psalms and hymns and spiritual songs to God with thankful hearts. 17And whatever you do or say, do it as a representative of the Lord Jesus, giving thanks through him to God the Father.
Verse 15 has 2 key points - peace and rule. We are to allow the peace of God rule in our hearts. The word ‘peace’ here is from the hebrew word - eirene which means one, peace, quietness, rest, and the word ‘rule’ is from the hebrew word - brabeuo which means to arbitrate. An arbitration is needed when 2 or more parties can’t come into agreement on a matter; they then call in an arbitrator who settles them i.e. makes peace. So this verse is telling us to allow or use peace as a judge in our hearts, to allow peace be made especially when we have 2 conflicting opinions in our hearts or lives. Peace should always be the yardstick, the judge.
The word here rendered rule brabeuetw--is commonly used in reference to the Olympic and other games. It means, to be a director, or arbiter of the public games; to preside over them and preserve order, and to distribute the prizes to the victors. The meaning here is, that the peace which God gives to the soul is to be to us what the brabeutes, or governor at the games, was to those who contended there. It is to preside over and govern the mind; to preserve everything in its place; and to save it from tumult, disorder, and irregularity - Albert Barnes NT Commentary
This peace is also not just some random type of peace; it is the peace of Christ i.e. the peace that Christ gives (John 14:27). This peace is a peace of assurance in the midst of chaos. When Jesus gave us this peace, he had just declared that he was leaving and all the woe that was going to come into the world and just after saying all that, he spoke peace to them. The peace comes from an assurance of Jesus - his promises, his word, his presence, the hope of seeing him again. no thing or person can give this kind of peace to one’s soul. Objects (e.g. the presence of money), people (the guarantee of help from a rich uncle) can promise some form of peace, but no one can give the overwhelming calm to the soul as the peace of Christ. This peace he has given to us and we are to use it and hold tightly to it.
In Verse 16, Paul was instructing the Colossians to be well instructed in the word of God, the logos i.e. the Bible. We are to ‘let’ the word of God dwell in us abundantly. Abundantly means without limit, fully, completely; we are to be filled up with the word of God. The word should be spoken about, taught, sung about. I believe many Christians fall short of this verse a lot. How many of us read our bibles daily? How many have ever completed the bible? How many can confidently quote scriptures off head? We are expected to be filled, experts of the word of God. Are you?
In Verse 17, Paul gives us a charge, a responsibility - Whatever you do, do it in the name of the Lord. Do it as a representative of Jesus. This whatever includes the word you speak and the actions you take, everything should be done like Jesus sent you on an errand to do them.
Begin with him, and end with him; invoke his name, and pray for his direction and support, in all that ye do; and thus every work will be crowned with all requisite success. - Adam Clarke’s Commentary
Our actions should be with a desire to honor him, his glory should be our aim in our actions and words. We should really be judging ourselves by the extent to which everything we do is done in the name of the Lord.