Mortification of Sin is the Constant Duty of Believers

The Mortification of Sin Chapter 2
We are not excused from this work of killing sin just because we have died with Christ virtually and have been raised to life. Jesus tells us how his Father deals with every branch in him that bears fruit, every true and living branch. "He prunes it, that it may bring forth more fruit" (Jn. 15:2). He prunes it, and he does so not just for a day or two, but while it is a branch in this world. Paul tells us how this was his practice: "I discipline my body, and keep it under control" (1 Cor. 9:27). "I do it daily; it is the work of my life; I do not neglect it; this is my business," he says.