Why Do Christians Do Bad Things?

There are generally two basic forms in which this question is asked. First, most Christians have at some point asked themselves, “If I’m a true Christian, why do I keep sinning?” Second, Christians and others have asked questions like, “How could Christians have committed such atrocities during the Crusades?” The two questions are different, but they have essentially the same theological and biblical answer. The answer requires us to understand what Scripture says is true of Christians in the threefold application of redemption. We must consider the Bible’s teaching about what has already happened to the Christian, what is happening to the Christian, and what has not yet happened to the Christian.

Already: What Has Happened to Christians (Regeneration, Justification, Adoption)

According to the Bible, when a person becomes a Christian, he has gone from death to life. He has experienced what we often call “regeneration.” This is foundational to our Christian identity. The Christian is a new creation (2 Cor. 5:17). He has been born again (John 3:3; 1 Peter 1:3). He was in darkness, and now he is in light (Acts 26:18; Eph. 5:8; 2 Cor. 6:14; 1 Peter 2:9). He was dead in trespasses and sins, and now he is alive together with Christ (Eph. 2:1–2; Col. 2:13). He was a slave to sin, and now he is a slave to righteousness (John 8:34; Rom. 6:1–23; Gal. 5:1). He had a heart of stone, and now he has a heart of flesh (Ezek. 11:19; 36:26). Regeneration and its fruit, conversion to Christ, signify a drastic change in identity.
Regeneration does not, however, purge the effects of our fallenness from our souls and bodies. Regeneration imparts spiritual life into the soul, but one’s history before regeneration is not changed. This means that a Christian will hate his sin, but he still might be attracted to the same sins as he was before conversion.

In the new birth (i.e., regeneration), we are effectually called, meaning that the Spirit not only calls us to embrace the Lord Jesus Christ by faith but also gives us the ability to respond to that call. When we place our faith in Christ, the Spirit unites us to Christ, from whom we receive the benefits of redemption, including “justification, adoption and sanctification, and the several benefits which in this life do either accompany or flow from them” (Westminster Shorter Catechism 32). In our union with Christ, justification, adoption, and sanctification are distinct yet inseparable benefits. In the act of justification, a person is pardoned of all sins and accepted as righteous in the sight of God only on account of the imputed righteousness of Christ received by faith alone (WSC 33). In the act of adoption, a person is received into the number and given a right to all the privileges of the sons of God (WSC 34). In the work of sanctification, a person begins to be renewed in his whole being after the image of God and is enabled more and more to die unto sin and live unto righteousness (WSC 35). Whereas justification and adoption are acts of God, sanctification is a work of God. Justification and adoption are punctiliar, one-time events. Sanctification is a progressive, lifelong work. So while the Christian is declared righteous in God’s sight on account of the imputed righteousness of Christ, he has not yet been entirely renewed in his whole being. At least not yet. As Martin Luther said, the Christian is simul justus et peccator—at the same time righteous and sinful. Regeneration makes a man new, yet he is an undeveloped man—a man who is being sanctified but has not yet been perfected.

Already/Not Yet: What Is Happening to Christians (Sanctification—Mortification and Vivification)

Some people, upon conversion, find that many of their old affections and sinful patterns immediately dissolve. Others experience a more gradual renewal of their desires. Although there is a sense that we are sanctified at our conversion, in that we are set apart as holy to the Lord, sanctification as a process is experienced at different rates.
Sanctification does not mean that the remnants of sin and corruption are eradicated at once. Rather, as Geerhardus Vos noted:

the renewing activity of the Holy Spirit does not immediately remove all evil from us and replace it with a completely holy and good person. He effects renewal at one point in order from there to cause His renewing and sanctifying work to take hold in increasingly wider circles.¹

In conversion, sin is dethroned in the heart of the believer, but it is not yet fully exterminated. Sin has no dominion over him who is under grace, but sin is still a present enemy. John Murray states: “Deliverance from the power of sin secured by union with Christ and from the defilement of sin secured by regeneration does not eliminate all sin from the heart and life of the believer. There is still indwelling sin.”² Therefore, sanctification can be messy. We become aware of the depths of sin in our lives slowly, and ethical blind spots may persist. Sanctification involves painfully slow progress that sometimes doesn’t look like progress at all. It often involves returning to the same sin over and over with increasing hatred of that sin. Nevertheless, the trajectory of the Christian life, because of union with Christ and the work of the Holy Spirit, is one of progressive renewal and conformity to the image of God.

The Westminster Shorter Catechism defines sanctification as the “work of God’s free grace, whereby we are renewed in the whole man after the image of God, and are enabled more and more to die unto sin, and live unto righteousness.” Sanctification has two aspects: dying unto sin, known as mortification, and living unto righteousness, known as vivification. Every Christian has indwelling sin that must be mortified in the power of the Spirit. Paul states as much in his own admission in Romans 7. Charles Hodge says,

The characteristic difference between the unrenewed and the renewed is not that the former are entirely sinful, and the latter perfectly holy; but that the former are wholly under the control of their fallen nature, while the latter have the Spirit of God dwelling in them, which leads them to crucify the flesh, and to strive after complete conformity to the image of God.³

In other words, the Spirit’s dwelling within us doesn’t eradicate sin entirely, but it does mean that the determinative and operative power in the Christian’s life is the sanctifying power of the Holy Spirit. The Christian still has vestigial sin, not governing sin, that needs to be mortified.⁴ Indwelling sin remains in the heart, but it is contradictory to and in conflict with the regenerate heart. This conflict will remain until our corruptible bodies are replaced with what is incorruptible.

So the Christian has been justified and adopted and he is being sanctified. When, if ever, will the Christian no longer sin?

Not Yet: What Has Yet to Happen to Christians (Glorification)

Throughout church history, some teachers have affirmed perfectionism—the idea that sanctification can be perfected in this life. The Reformation, however, rejected this view. Perfection will indeed come for the Christian, but not in this life. Martin Luther said:

There be two contrary captains in you, the spirit and the flesh. In justification God hath stirred up in your bodies a strife and a battle; the flesh and the spirit at war with the other. . . . If we were pure from all sin, and were inflamed with perfect love both towards God and our neighbor, then should we indeed be righteous and holy through love, and God would require no more of us. This is not done in the present life, but is deferred until the life to come. We receive here the first fruits of the spirit, so that we begin to live, howbeit very slenderly.⁵

The error of the perfectionists is an over realized eschatology—that is, an expectation that what is promised for the final state of glory will be experienced now. Indwelling sin remains until glorification, however, and glorification doesn’t happen until death: “The souls of believers are at their death made perfect in holiness, and do immediately pass into glory; and their bodies, being still united to Christ, do rest in their graves till the resurrection” (WSC 37). John Owen says:

Indwelling sin continues to live in believers in some measure and degree while we are in this world. . . . There is a remaining darkness to be gradually removed. . . . We have a ‘body of death’ (Rom. 7:24); from which we are not delivered but by the death of our bodies (Phil. 3:21).⁶

Until death, our sanctification remains imperfect, and glorification remains a future, albeit Spirit-guaranteed (Eph. 1:13–14), reality. The Canons of Dort capture this tension well:

Whom God calls, according to His purpose, to the communion of His Son, our Lord Jesus Christ, and regenerates by the Holy Spirit, He delivers also from the dominion and slavery of sin in this life; though not altogether from the body of sin and from the infirmities of the flesh, so long as they continue in this world. (5.1)

A Christian is someone who has been renewed (regeneration), is being renewed (sanctification), and will be renewed (glorification). His sin has been dealt with judicially (justification), it is being dealt with progressively (sanctification), and it will be dealt with permanently (glorification). These nuances help us make sense of the presence of sin in the life of a Christian. While we saints remain in these bodies of sin in a fallen world, we continue to battle our own flesh and its non-reigning, extant sin—which is why Christians still do bad things. But one day, coming soon, we will do only that which is good, in glorified bodies and a renewed world that aren’t polluted by sin and corruption. Come quickly, Lord Jesus.

Editor’s Note: This article was originally published on October 12, 2022.