If a person genuinely repents for their past sins and sincerely trusts in Jesus Christ for eternal salvation (i.e., becomes a true Christian, not just a Christian in name only), does their nature change?  [Note:  For purposes of this article, a person’s nature refers to the fundamental character of that person.]

The scripture that seems to most succinctly answer this question is 2 Corinthians 5:17, which states, “[I]f anyone is in Christ, he is a new creation; old things have passed away; behold, all things have become new.”

[Note:  When we quote Scripture in this article, we use the wording in the New King James Version of the Bible, except when we are quoting a source that uses a different translation.  With specific regard to 2 Corinthians 5:17, note that some Bible translations use the term “creature,” rather than “creation.”]

In addressing the significance of 2 Corinthians 5:17, Peter Pett’s Commentary on the Bible provides what we consider to be the basic changes in the nature of a person after that person becomes a true Christian.  According to Pett,

[I]f any man is in Christ he is a new creature, newly created in Christ. When a man is ‘in Christ’ through his response to the word of the cross, everything is changed for him. All the old things, his old life, his old ambitions, his old aims, are passed away. He is a transformed person. His whole life has become new. He is a new creation. He lives only for Christ, and as it were allows Christ to live out His life through him (2 Corinthians 5:15). He is born anew of the Spirit (John 3:5-6), and made a partaker of the divine nature (2 Peter 1:4).

The word ‘new’ means ‘something different from before’. It means here totally new. He is a transformed person. What is common to both interpretations is that for the man in Christ life changes. He has a new perspective. He lives a new life. He is thus a ‘new’ person.

Although we agree in general with what Pett says, we think his statement that a person who becomes a Christian “lives only for Christ” is too exclusive.  Although a person who becomes a Christian should give top priority to Jesus Christ with regard to how they conduct their life, this does not mean that they are not responsible for the welfare of other people, especially their family.

With regard to the same verse of scripture, Matthew Henry’s Complete Commentary on the Bible provides perspective that is similar to that of Pett as to the basic changes in the nature of a person after that person becomes a true Christian.  Henry states,

For if any man be in Christ, if any man be a Christian indeed, and will approve himself such, he is, or he must be, a new creature. . . . Some read it, Let him be a new creature. This ought to be the care of all who profess the Christian faith, that they be new creatures; not only that they have a new name, and wear a new livery, but that they have a new heart and new nature. And so great is the change the grace of God makes in the soul, that, as it follows, old things are passed away – old thoughts, old principles, and old practices, are passed away; and all these things must become new.

Likewise, John Gill’s Exposition on the Whole Bible provides perspective regarding 2 Corinthians 5:17 that relates to the basic changes in a person’s nature after that person becomes a true Christian.  Gill says,

[T]here is a new course of life, both of faith and holiness; a new way of serving God through Christ by the Spirit, and from principles of grace; a new, another, and better righteousness is received and embraced; new companions are sought after, and delighted in. . . .

In addressing the same scripture, Adam Clarke Commentary mentions several examples of the general types of changes that occur in a person’s nature after that person becomes a true Christian.   Clarke declares,

It is vain for a man to profess affinity to Christ according to the flesh, while he is unchanged in his heart and life, and dead in trespasses and sins; for he that is in Christ, that is, a genuine Christian, having Christ dwelling in his heart by faith, is a new creature; his old state is changed: he was a child of Satan, he is now a child of God; he was a slave of sin, and his works were death; he is now made free from sin, and has his fruit unto holiness, and the end everlasting life. He was before full of pride and wrath; he is now meek and humble. He formerly had his portion in this life and lived for this world alone; he now hath God for his portion, and he looks not at the things which are seen, but at the things which are eternal. Therefore, old things are passed away.

Barnes’ Notes on the Whole Bible, in discussing the implications of 2 Corinthians 5:17, also includes several examples of the general types of changes in a person’s nature after that person becomes a true Christian.  According to Barnes,

The affirmation here is universal, “if any man be in Christ;” that is, all who become true Christians – undergo such a change in their views and feelings as to make it proper to say of them that they are new creatures. No matter what they have been before, whether moral or immoral; whether infidels or speculative believers; whether amiable, or debased, sensual and polluted yet if they become Christians they all experience such a change as to make it proper to say they are a new creation.

The idea evidently is, not that [a Christian] ought to be a new creature, but that he is in fact; not that he ought to live as becomes a new creature – which is true enough – but that he will in fact live in that way, and manifest the characteristics of the new creation.

[The phrase “a new creature”] means a new creation in a moral sense. . . . It means, evidently, that there is a change produced in the renewed heart of man that is equivalent to the act of creation, and that bears a strong resemblance to it – a change, so to speak, as if the man was made over again, and had become new.

Their former prejudices, opinions, habits, attachments pass away. Their supreme love of self passes away. Their love of sins passes away. Their love of the world passes away. Their supreme attachment to their earthly friends rather than God passes away. Their love of sin, their sensuality, pride, vanity, levity, ambition, passes away. There is a deep and radical change on all these subjects – a change which commences at the new birth; which is carried on by progressive sanctification. . . .

In reference to the same scripture, Matthew Poole’s English Annotations on the Holy Bible emphasizes that those who are not true Christians will not have the new nature that true Christians experience.   Poole says,

Old things are passed away, old affections, passions, notions, etc. He hath the same soul, but new qualities, new apprehensions in his understanding, new inclinations in his will and affections, new thoughts, counsels, and designs. The predicate showeth, that the term, be in Christ, cannot be understood of those that are only in the church, and turned from paganism to the Christian faith; for there are many such in the world, in whom there is no new creation, and who have in them nothing of this new creature.

The winter 2020-2021 edition of the Leader Guide for Explore the Bible, a publication that is used by many churches in teaching the Bible, provides the following relevant comments, which pertain to Luke 9:23:

[N]o one can follow Christ while pursuing his or her own agenda.  A disciple must deny himself.  This requirement does not mean simply giving up certain things but denying one’s desires and ambitions in favor of God’s pleasure and glory.

[J]ust as Jesus took up His cross to provide salvation, even so each believer must take up his cross to follow Christ.  The believer’s cross is not some burden experienced in life.  It is a lifestyle of self-sacrificing love that refuses to live for selfish interests.

Conclusions

Our concern with all of the preceding sources is that although they indicate that positive changes in the nature of people who become true Christians should be evident after they become a Christian, they do not indicate that at least some – and probably many – of the positive changes are not likely to take place for years.  Certainly, true Christians should have a desire to live a more righteous life, but they are  unlikely to manifest positive changes in every aspect of their nature immediately after  – or even soon after – they become a Christian.

A lot of true believers may have significant improvement in some aspects of their fundamental character, but may not show much, if any, evidence that other aspects of their nature have improved, even many years after becoming a Christian,  This can occur if they do not understand the importance of living a more righteous life and/or they are reluctant to commit to trying to do so, because of their perception of the difficulty of living such a life.  Therefore, greater knowledge and understanding of what the Bible teaches is generally necessary to motivate them to strive to live a more righteous life.

Even if a Christian has a genuine desire to demonstrate a righteous nature, that person may become discouraged by his (or her) lack of success in this regard.  For a Christian to be able to consistently demonstrate a righteous nature, it is necessary for that person to maintain a desire to give God’s will top priority in his (or her) life.  Like Jesus Christ, each of His followers (i.e., every Christian) must be willing to sincerely say to God, “Not my will, but Yours, be done.”

[For related articles, click on “Can Jesus Christ Be a Person’s Savior but Not Their Lord?” and/or “Can Anyone Except God Be Holy?”]