Sanctification is a major theme of the New Testament. Just about every author, if not all, take the time to describe how a Christian should live in an unholy world. Many of these instructions come in the form of Christians relating to unbelievers around them, or Christians relating to other Christians. However, the common principle of sanctification is that both the wrestle against sin and the journey towards a God honouring life first take place in a person's heart. To progress in holiness, the Christian must be intentional about both putting off sin and putting on Christ. Thomas Watson succinctly describes this battle by saying, “Till sin be bitter, Christ will not be sweet.” The apostle Paul said it a different way in his letter to the Romans. Speaking to the church, he said, “But put on the Lord Jesus Christ, and make no provision for the flesh, to gratify its desires” (Romans 13:14). Sin must be killed, and Christ must be our prize.
To first deal with the battle, we would do well to look to Romans 6. At this point in the letter, Paul is instructing Christians on the realities of sanctification. In Romans 6:11-13, he specifically states the need for believers to battle sin.
"So you also must consider yourselves dead to sin and alive to God in Christ Jesus. Let not sin therefore reign in your mortal body, to make you obey its passions. Do not present your members to sin as instruments for unrighteousness, but present yourselves to God as those who have been brought from death to life, and your members to God as instruments for righteousness."
The start of this passage deals with a change of thinking before it calls for a change in action. Paul calls all Christians to think of themselves as though they were dead to sin. In saying this, Paul wants us to consider how a dead person responds to the desire of sin. The answer is that they do nothing and can do nothing to give into sin. They have no appetite for it because they are dead. That is how we are to view our relationship to sin; in light of Christ dying for our sin and God removing it from us.
Once we view sin through this lens, we can begin to fight it in our lives properly. Paul continues by saying sin should not have the power to make the believer respond to it. At first glance, this may seem like a passive feature of the Christian life, but in reality, this is a daily wrestle for all believers. To be disobedient to the temptations of sin takes deliberate action both mentally and physically. John Owen wrote on this very topic in his work The Mortification of Sin, saying, “Do you mortify; do you make it your daily work; be always at it whilst you live; cease not a day from this work; be killing sin or it will be killing you.” To deny ourselves of our sinful desires takes both proper thinking and intentional choices.
As we look at the imperatives to live a holy life through the removal of sin, we should not overlook that these instructions often come in the context of loving Christ above all. To grow in sanctification, there must be both the absence of sin and the presence of good works. This is impossible without prizing Christ. In Romans 13:14, Paul gives us a visual of what our fellowship with Christ should look like. He says that we should “put on the Lord Jesus Christ.” This is a useful analogy showing us to put on Christ as we put on our everyday clothes. The nearness of our clothing is just a small picture of how close our fellowship with Christ ought to be. To put on Christ is to grow in knowledge and love for him, largely through means of grace like prayer, the study of Scripture, and preaching the gospel to ourselves. It is only then that sin can be properly fought.
To put off sin and grow in fellowship with Christ has tangible results. To present ourselves “to God as instruments for righteousness” (Romans 6:13), we need to be walking with Christ, for we will never accomplish this on our own. In light of the Trinity, Christ helps Christians produce these good works through the indwelling Spirit. Both Romans 8 and Galatians 5 make it clear that the source and power for righteous living come from the Holy Spirit. Putting on Christ includes being filled with the Spirit so that we can grow in good works.
Crucifying the flesh and growing in love for Christ and others is the essence of progressive sanctification. This is a life-long reality for all Christians. It will not be mastered here on earth, but success will yield rewards from God, and more importantly, it will bring glory to God. It is important to note that putting off sin and putting on Christ cannot be easily separated. They are two sides of the same coin. Sin can't be overcome without Christ and fellowship with Christ cannot grow without putting away sin.
Does this leave us stuck? No, we are not stuck, for through our prayers, God initiates our victory on both fronts. Our responsibility is to be faithful to Him and praise Him for the victory He gives. When sin is bitter and Christ is sweet, we can be assured that God is working in our lives.