In Colossians 3:1-2, Paul encourages us to seek the good things to be specified later in the chapter. One reason to seek those things is that “you are dead, and your life is hidden with Christ in God” (3:3). The other reason is that you have been raised with him (3:1). That is sanctification, in fact, the entire Christian life.
This chapter reads like a conflation of Romans 6 and Romans 12 with some elements of Ephesians 5-6, where Paul tells describes the Spirit-filled life. How is the Christian to be filled with the Holy Spirit (Ephesians 5)? In the first person of Luther’s Small Catechism, I am filled with the Spirit by continuing to “believe in Jesus Christ” since it is the Lord and Giver of life who “sanctifies the whole Christian Church on earth.” Indeed, I am not in any way sanctified “by my own reason or strength.”