An important question every Christian must ask is, What does it mean to be a disciple of Christ? Very simply, a disciple will observe all that Christ commanded. In other words, a disciple of Jesus Christ will be characterized by certain behaviors. Christians are a new people of God (1 Peter 2:9) whose behavior should emerge from and reflect their biblical beliefs and values. This is why Scripture gives such attention to the behavior of Christians; it should be holy as God is holy (1 Peter 1:15–16). Although Christians are new creatures (2 Cor 5:17) with new hearts of obedience to Christ (Rom 6:17–18), holy behavior is not something that comes automatically. Observing Christ’s commands, as the Great Commission explicitly states, is something that must be taught. In other words, true conversion is not simply assent to certain facts; it is a life-changing entrance into communion with God. It is “turn[ing] to God from idols to serve a living and true God” (1 Thess 1:9–10).
Understanding that discipleship begins with evangelism but involves more, the question remains as to how Christians are shaped as disciples. Certainly much of what is involved with such Christian sanctification is coming to know more truth. Without a proper set of beliefs, one will not behave in a manner worthy of Christ. However, data transmission is not all there is to discipleship for at least three reasons. First, Christian behavior is more than simply a collection of right beliefs. Jesus did not just say, “teaching them all that I have commanded”; he said, “teaching them to observe all that I have commanded.” Christian behavior is a collection of skills, and development of a skillset requires more than a certain amount of knowledge.
Second, making disciples is more than data transmission because the reality is that most actions are not the result of deliberate, rational reflection upon beliefs. Some are, but most of how people act on a daily basis is due to ingrained habits. We may understand the gospel and diligently learn biblical doctrines, but that will not necessarily make a disciple who is characterized by Christian moral living, especially if we have many habitual behaviors that conflict with biblical living. A drug addict will still have to deal with his addiction, a petty thief may find himself unintentionally slipping things off the shelf into his pocket, and a lazy husband will have difficulty finding the energy necessary to help with the kids. Old habits die hard, even for a Christian.
Third, whether or not people are acting on the basis of a deliberate decision or a habitual response, people ultimately will act not primarily based on the knowledge in their minds, but rather on the inclinations of their hearts. A child who is terrified of dogs will not pet one no matter how many statistics you give her about the docile nature of domesticated canines. A man whose heart is captivated by pornography will sin continually no matter how much he knows it is wrong. Another way of saying this is that people act more based on their feelings than on their knowledge. The way many evangelicals try to combat this reality is to urge people to live according to their beliefs rather than their hearts, but it is not quite that simple. The problem is not that we have replaced what drives our actions with our hearts instead of our minds. We cannot help but be driven by the inclinations of our hearts, and philosophers from Plato to Augustine to Edwards to Lewis all recognized this. If the intellect and the heart conflict, we will always do what we want to do rather than what we know we should do; this is the nature of humanity. Thus in order to cultivate holy living, we must concern ourselves with nurturing moral virtue.