We are 'clothed' with our conduct as illustrated in Col 3:5 'put to death your members'; Col 3:8 'put off...'; and Col 3:12 'put on...'. Death is separation from God (Gen 3:17; Rom 6:23; Rom 4:5). Union with Christ equals death to sin (Rom 6:1-7); our union includes the fact that we are 'alive to God' (Rom 6:8); this condition is permanent (Rom 6:9-10). Separation and sanctification is a matter of focus of soul -- 'reckon ourselves dead to sin' and 'present ourselves to God' (Rom 6:11-12; Rom 12:2; 1Th 4:3). How? Depart from iniquity (2Ti 2:19-22); Joseph illustrates separation by fleeing temptation.
Paul never met the Colossians but wrote to them from a Roman prison around 62 AD to counter misconceptions of his day. It magnifies the character of Jesus Christ more than any other book in the New Testament, and counters misconceptions of our day as well. The key verse may well be Col 1:18 "...that in all things, He might have preeminence."