In Colossians 3, Paul continues to build the foundations for the people to see and experience the life of Christ in their life.  After teaching them to life in Christ the way the first recieved him, by grace through faith, then to reject the lies that any religious activity or traditions of men will be useful in overcoming sin, he gives them the next building blocks to real life.  Seek Christ, kill the mindsets and practices that bring death and replace them by clothing themselves in Christ.  This pattern of life, empowered but the Holy Spirit, leads people to live and experience the life of Christ, filled to the brim and spill over to the world.