Scripture reading: John 8:31-36

Immunity is the ability of the body to recognise, resist, and eliminate harmful organisms or substances such as bacteria, viruses, parasites, and toxins. In simple terms, immunity is the body’s defence system against disease. This immunity can be innate—the natural immunity one is born with—or acquired, that is, immunity that develops after exposure to a pathogen.

Acquired immunity can be active or passive. Active immunity occurs when the body produces its own antibodies through natural infection or vaccination. An example is the immunity one gains after recovering from chickenpox. Passive immunity, on the other hand, is immunity derived from antibodies received from another source. An example is the administration of Rho(D) Immune Globulin to prevent rhesus isoimmunization, as we discussed in last week’s devotional, “Sensitisation.”

The truth is that the Christian is not entirely immune from sin. Even after salvation, believers still struggle with sin. We will not be completely free from it until we die or until Jesus returns. Yet becoming a Christian results in a changed life (2 Corinthians 5:17). When a person accepts Jesus as Lord and Saviour, he becomes a new creation. He moves from a kingdom where, by virtue of his sinful nature, he could not help but sin, into a new domain where he is clothed with Christ. Christ becomes his righteousness. In that sense, Christ becomes his new innate immunity by virtue of the new birth.

Instead of producing the works of the flesh (Galatians 5:19–21), the believer begins to display the fruit of the Spirit (Galatians 5:22–23), as the indwelling Holy Spirit increasingly takes control of his life. This transformation does not occur instantly, but it does occur progressively. The old nature begins to lose its dominance. The flesh begins to die.

Along the way, the believer also develops something like acquired immunity—a growing resistance to sin. Through conscious striving, repentance, and sensitivity to the Spirit’s guidance, he learns to keep sinful acts at bay. If a person claims to believe yet shows no evidence of a changed life, it raises serious questions about the genuineness of his faith.

And sometimes, the believer may still fall. But he does not remain in the dirt. That fall often strengthens his resolve to rise again and continue pressing forward. In that sense, each failure, met with repentance, builds a kind of active immunity against repeating the same sin.

The difference between a sinning unbeliever and a sinning believer is this: one loves his sin, while the other hates it.

The believer who stumbles regrets it, confesses it, and longs never to repeat it. He seeks God’s grace and power to avoid it in the future. He does not ask how much he can sin and still be considered a Christian. Rather, he asks how he can avoid even the appearance of sin.

The believer may stumble, but he does not settle in sin. Grace lifts him, repentance cleanses him, and the Spirit strengthens him. Over time, the soul that walks with Christ becomes increasingly resistant to the very sins that once mastered it.

Just as the body develops immunity to resist disease, the believer must develop a growing resistance to sin. The goal is not to see how close we can live to sin, but how far we can live from it. A healthy spiritual life is one that increasingly rejects what once infected it.

To conclude, let us reflect on this question: If I truly belong to Christ, do I see evidence that my desires, attitudes, and actions are gradually being transformed?

Let us pray. Heavenly Father, thank You for the new life we have in Christ. Help us to grow in our resistance to sin and to walk daily in the power of Your Spirit. When we stumble, grant us hearts that quickly repent and return to You. Shape our lives so that we increasingly love righteousness and hate sin. In Jesus’ name, Amen.

Thank you for joining us for today’s encouragement. If this message blessed you, kindly share it with someone who may also be encouraged by it.

Until next time, stay blessed.