The Puritan John Owen, in his classic work The Mortification of Sin, describes what the Christian life requires: “The choicest believers, who are assuredly freed from the condemning power of sin, ought yet to make it their business all their days to mortify the indwelling power of sin.” Owen sees mortification as our life’s work—it is to be done “all [our] days” because perfection will not be realized this side of heaven.
A New Creation in Christ
Even as the Bible is clear that perfection is not possible in this life, God’s Word is equally clear that Christians are to grow in godliness. The theological reason for this has everything to do with what happens at regeneration: we are made new creatures in Christ. This is the astonishing truth Paul declares in 2 Corinthians 5:17: “Therefore, if anyone is in Christ, he is a new creation. The old has passed away; behold, the new has come.”
To be a new creation is the biography of every Christian. It is a promise for all those who are “in Christ”—that is, united by faith to the risen and exalted Lord. The term “new creation” carries with it the idea of the sovereign, creative power of God. Paul invoked this idea earlier when he alluded to the power of God in creating light and the making of a Christian: “For God, who said, ‘Let light shine out of darkness,’ has shone in our hearts to give the light of the knowledge of the glory of God in the face of Jesus Christ” (2 Cor. 4:6).
What we learn is that Christianity is not moral tweaking. It is not simply brushing off our old selves, as if we’re merely dirty. Christianity is not ultimately about new habits or a new outlook, although it includes those things. Christianity is about a complete and exhaustive overhaul. Nothing less than a new creation.
A Christian is one who has experienced the new covenant promise of Ezekiel 36:26–27, where God proclaims what will be accomplished in Christ by the Spirit:
And I will give you a new heart, and a new spirit I will put within you. And I will remove the heart of stone from your flesh and give you a heart of flesh. And I will put my Spirit within you, and cause you to walk in my statutes and be careful to obey my rules.
The Christian has been given a new heart and the very Spirit of God so that we now “walk in newness of life” (Rom. 6:4).
The Apostle says that the “old has passed away.” With the cross of Christ we have the end of the old covenant as well as the end of the old life of those who are now in Christ. Our old life of godless, self-centered, fleshly living has been crucified.