“If these vices are not, eventually, to kill the one who practices them, they must themselves be ‘put to death’. The old word ‘mortify’…has now acquired exactly the wrong sense, implying just such a regime of ascetic discipline as Paul has declared to be worse than useless (2:20-23). ‘Mortification’ like that avoids dealing directly with the sin itself. Paul’s recommended treatment is simpler and more drastic.
To put something to death you must cut off its lines of supply: it is futile and self-deceiving to bemoan one’s inability to resist the last stages of a temptation when earlier stages have gone by unnoticed, or even eagerly welcomed. This does not mean setting up a new hedge around the law, such as branding all theatrical performances (or whatever) as inherently ‘sinful’. Rather, every Christian has the responsibility, before God, to investigate the lifelines of whatever sins are defeating him personally, and to cut them off without pity. Better that than have them eventually destroy him.”
Put to death the old self by cutting off the lines of supply that pump the flesh into our being, and to put on the new man but opening such lines of supply so that the life-giving Christ might reach every part of us.