Drawing on the classic call to “be killing sin or it will be killing you,” this sermon defines mortification, sin, and the lusts and deeds of the flesh, then presents mortifying sin as a Christian duty. Because God is infinitely holy, growing in holiness means growing in a corresponding hatred of sin, letting Christ reign in the body rather than sin.
The message works through the danger sin poses, warns against trusting the flesh, and shows that in Christ our sin has already been condemned in the flesh, while Christ, who knows our weakness, helps us fight it. It closes with practical rules for mortifying sin — submitting to God, mortifying all sin rather than just one, and confessing sin honestly — as a battle plan for the Christian life.