Mortification of Sin:
Mortification of Sin has been defined as "The discipline and duty of resisting our inclination to sin by laying hold of the power of the Holy Spirit who resides in each believer. The Spirit makes effective in believers the benefit of Christ’s atoning death on the cross, the great redemptive act of love and power which broke the dominion of sin in the lives of those who have been justified by simple faith in Jesus Christ." (*citation below)
Listen to this good word from John Fonville: "We deny ourselves. We discipline ourselves for the purpose of godliness, as Paul says, but it is the Spirit who sanctifies, not our efforts. We work BECAUSE God works in us- Philippians 2. There is a place to look inward (Rom. 7:13-24). But, the key is we do not stay there. Having been made aware (painfully aware at times) of our failure to live up to who we are in Christ and to keep God's holy, just and good law, we immediately look out of ourselves and outward in faith to Christ alone (Rom. 7:24-8:1)."
We know that justification is wholly outside of ourselves. Christ alone makes us righteous, by His righteousness. Christ alone atoned for us, for the forgiveness of our sins. Christ alone was buried and rose again so that we are resurrected to new life now, and in the world to come. Yet sometimes we become confused and perplexed about our sanctification. The WSC provides us comfort. Even sanctification is a "gift of God's free grace." He does not fail to conform us to the image of His Son. So, do not despair. As you are aware of the reality and gravity of your sin, humble yourself, confess, then rejoice! Your acceptance with God has not changed, because He is faithful. He lived for you. He died for you. He is ever interceding for you.
*Missouri Presbytery Ad Hoc Committee to Investigate Memorial Presbyterian Church for Hosting the Revoice 18 Conference in July 2018