Families are often glad to pass clothing from one child to another.  It is economical but also allows the older children to say, ‘I used to wear that’: a sort of bonding with younger siblings.  On the other hand, rebellious children can refuse to wear what is conventional for the family, and dress differently as a way of expressing that they do not respect the family values.  What we wear identifies us: an external sign of our loyalties and values.  Using that picture, Paul tells the believers in Colossae that they need 'new clothes' because they belong to Christ.
 
These 'clothes' are not physical garments made of fabric, but the attitudes and behaviour of Christ.  They are seen in the way we act and react towards other people.  Compassion, kindness, humility, gentleness and patience are not natural for sinful people.  And they do not automatically become our pattern of life the moment we come to Jesus; they have to be 'put on'.  That involves a decision not only to believe in Christ but to value His lifestyle, and learn to live like Him.  Of course, He will help us and the Holy Spirit will motivate us (Galatians 5:22-24).  But we must choose to react differently.  Then we have the responsibility to curb our old habits and embrace a whole new way of living.

Paul describes Christians as “God’s chosen people”.  In the Old Testament the Jews were the ‘chosen people’.  They were to be the example of God’s loving grace and holiness to the rest of the world.  But although God set His love on them, they rebelled.  Not all who were descended from Abraham are in God’s family (Romans 9:6).  But everybody who trusts in Jesus will be made children of God (John 1:12-13).  If that is you, then please be assured that God has chosen you; you are holy (specially reserved) for Him.  Therefore, put on His character and live like Him.   
 
Initially, like new clothes, the new lifestyle may seem strange or even uncomfortable at first.  We might disappoint ourselves as we instinctively react to people and circumstances in the old selfish way, not caring about others.  But bit by bit we learn to love Christ's 'clothes' and do our best to wear them for His glory (Philippians 2:3-8).  Then our active decision to relate and react to others in a Christ-like way, will get translated into a new way of life as we pray for help, confess every failure and give thanks for every personal victory won.  God has chosen us to belong to Him.  So let us wear His 'uniform' of love.  Then others will know that Jesus Christ is powerful to transform people.